| Message ID | 1433343154-5613-1-git-send-email-ludovic.desroches@atmel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Le 03/06/2015 16:52, Ludovic Desroches a écrit : > Using _bh variant for spin locks causes this kind of warning: > Starting logging: ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 3 at /ssd_drive/linux/kernel/softirq.c:151 > __local_bh_enable_ip+0xe8/0xf4() > Modules linked in: > CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.1.0-rc2+ #94 > Hardware name: Atmel SAMA5 > [<c0013c04>] (unwind_backtrace) from [<c00118a4>] (show_stack+0x10/0x14) > [<c00118a4>] (show_stack) from [<c001bbcc>] > (warn_slowpath_common+0x80/0xac) > [<c001bbcc>] (warn_slowpath_common) from [<c001bc14>] > (warn_slowpath_null+0x1c/0x24) > [<c001bc14>] (warn_slowpath_null) from [<c001e28c>] > (__local_bh_enable_ip+0xe8/0xf4) > [<c001e28c>] (__local_bh_enable_ip) from [<c01fdbd0>] > (at_xdmac_device_terminate_all+0xf4/0x100) > [<c01fdbd0>] (at_xdmac_device_terminate_all) from [<c02221a4>] > (atmel_complete_tx_dma+0x34/0xf4) > [<c02221a4>] (atmel_complete_tx_dma) from [<c01fe4ac>] > (at_xdmac_tasklet+0x14c/0x1ac) > [<c01fe4ac>] (at_xdmac_tasklet) from [<c001de58>] > (tasklet_action+0x68/0xb4) > [<c001de58>] (tasklet_action) from [<c001dfdc>] > (__do_softirq+0xfc/0x238) > [<c001dfdc>] (__do_softirq) from [<c001e140>] (run_ksoftirqd+0x28/0x34) > [<c001e140>] (run_ksoftirqd) from [<c0033a3c>] > (smpboot_thread_fn+0x138/0x18c) > [<c0033a3c>] (smpboot_thread_fn) from [<c0030e7c>] (kthread+0xdc/0xf0) > [<c0030e7c>] (kthread) from [<c000f480>] (ret_from_fork+0x14/0x34) > ---[ end trace b57b14a99c1d8812 ]--- > > It comes from the fact that devices can called some code from the DMA Isn't there a typo in the previous line? > controller with irq disabled. _bh variant is not intended to be used in > this case since it can enable irqs. Switch to irqsave/irqrestore variant to > avoid this situation. > > Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> > Cc: stable@vger.kernel.org # 4.0 and later Yes: Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> > --- > drivers/dma/at_xdmac.c | 85 ++++++++++++++++++++++++++++---------------------- > 1 file changed, 48 insertions(+), 37 deletions(-) > > diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c > index 9b602a6..4a7e9c6 100644 > --- a/drivers/dma/at_xdmac.c > +++ b/drivers/dma/at_xdmac.c > @@ -421,8 +421,9 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx) > struct at_xdmac_desc *desc = txd_to_at_desc(tx); > struct at_xdmac_chan *atchan = to_at_xdmac_chan(tx->chan); > dma_cookie_t cookie; > + unsigned long irqflags; > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, irqflags); > cookie = dma_cookie_assign(tx); > > dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n", > @@ -431,7 +432,7 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx) > if (list_is_singular(&atchan->xfers_list)) > at_xdmac_start_xfer(atchan, desc); > > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, irqflags); > return cookie; > } > > @@ -591,11 +592,13 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, > unsigned int sg_len, enum dma_transfer_direction direction, > unsigned long flags, void *context) > { > - struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > - struct at_xdmac_desc *first = NULL, *prev = NULL; > - struct scatterlist *sg; > - int i; > - unsigned int xfer_size = 0; > + struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > + struct at_xdmac_desc *first = NULL, *prev = NULL; > + struct scatterlist *sg; > + int i; > + unsigned int xfer_size = 0; > + unsigned long irqflags; > + struct dma_async_tx_descriptor *ret = NULL; > > if (!sgl) > return NULL; > @@ -611,7 +614,7 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, > flags); > > /* Protect dma_sconfig field that can be modified by set_slave_conf. */ > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, irqflags); > > /* Prepare descriptors. */ > for_each_sg(sgl, sg, sg_len, i) { > @@ -622,8 +625,7 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, > mem = sg_dma_address(sg); > if (unlikely(!len)) { > dev_err(chan2dev(chan), "sg data length is zero\n"); > - spin_unlock_bh(&atchan->lock); > - return NULL; > + goto spin_unlock; > } > dev_dbg(chan2dev(chan), "%s: * sg%d len=%u, mem=0x%08x\n", > __func__, i, len, mem); > @@ -633,8 +635,7 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, > dev_err(chan2dev(chan), "can't get descriptor\n"); > if (first) > list_splice_init(&first->descs_list, &atchan->free_descs_list); > - spin_unlock_bh(&atchan->lock); > - return NULL; > + goto spin_unlock; > } > > /* Linked list descriptor setup. */ > @@ -673,13 +674,15 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, > xfer_size += len; > } > > - spin_unlock_bh(&atchan->lock); > > first->tx_dma_desc.flags = flags; > first->xfer_size = xfer_size; > first->direction = direction; > + ret = &first->tx_dma_desc; > > - return &first->tx_dma_desc; > +spin_unlock: > + spin_unlock_irqrestore(&atchan->lock, irqflags); > + return ret; > } > > static struct dma_async_tx_descriptor * > @@ -692,6 +695,7 @@ at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, > struct at_xdmac_desc *first = NULL, *prev = NULL; > unsigned int periods = buf_len / period_len; > int i; > + unsigned long irqflags; > > dev_dbg(chan2dev(chan), "%s: buf_addr=%pad, buf_len=%zd, period_len=%zd, dir=%s, flags=0x%lx\n", > __func__, &buf_addr, buf_len, period_len, > @@ -710,16 +714,16 @@ at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, > for (i = 0; i < periods; i++) { > struct at_xdmac_desc *desc = NULL; > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, irqflags); > desc = at_xdmac_get_desc(atchan); > if (!desc) { > dev_err(chan2dev(chan), "can't get descriptor\n"); > if (first) > list_splice_init(&first->descs_list, &atchan->free_descs_list); > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, irqflags); > return NULL; > } > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, irqflags); > dev_dbg(chan2dev(chan), > "%s: desc=0x%p, tx_dma_desc.phys=%pad\n", > __func__, desc, &desc->tx_dma_desc.phys); > @@ -1036,6 +1040,7 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, > | AT_XDMAC_CC_SIF(0) > | AT_XDMAC_CC_MBSIZE_SIXTEEN > | AT_XDMAC_CC_TYPE_MEM_TRAN; > + unsigned long irqflags; > > dev_dbg(chan2dev(chan), "%s: src=%pad, dest=%pad, len=%zd, flags=0x%lx\n", > __func__, &src, &dest, len, flags); > @@ -1051,9 +1056,9 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, > > dev_dbg(chan2dev(chan), "%s: remaining_size=%zu\n", __func__, remaining_size); > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, irqflags); > desc = at_xdmac_get_desc(atchan); > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, irqflags); > if (!desc) { > dev_err(chan2dev(chan), "can't get descriptor\n"); > if (first) > @@ -1123,6 +1128,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, > int residue; > u32 cur_nda, mask, value; > u8 dwidth = 0; > + unsigned long flags; > > ret = dma_cookie_status(chan, cookie, txstate); > if (ret == DMA_COMPLETE) > @@ -1131,7 +1137,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, > if (!txstate) > return ret; > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, flags); > > desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node); > > @@ -1141,8 +1147,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, > */ > if (!desc->active_xfer) { > dma_set_residue(txstate, desc->xfer_size); > - spin_unlock_bh(&atchan->lock); > - return ret; > + goto spin_unlock; > } > > residue = desc->xfer_size; > @@ -1173,14 +1178,14 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, > } > residue += at_xdmac_chan_read(atchan, AT_XDMAC_CUBC) << dwidth; > > - spin_unlock_bh(&atchan->lock); > - > dma_set_residue(txstate, residue); > > dev_dbg(chan2dev(chan), > "%s: desc=0x%p, tx_dma_desc.phys=%pad, tx_status=%d, cookie=%d, residue=%d\n", > __func__, desc, &desc->tx_dma_desc.phys, ret, cookie, residue); > > +spin_unlock: > + spin_unlock_irqrestore(&atchan->lock, flags); > return ret; > } > > @@ -1201,8 +1206,9 @@ static void at_xdmac_remove_xfer(struct at_xdmac_chan *atchan, > static void at_xdmac_advance_work(struct at_xdmac_chan *atchan) > { > struct at_xdmac_desc *desc; > + unsigned long flags; > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, flags); > > /* > * If channel is enabled, do nothing, advance_work will be triggered > @@ -1217,7 +1223,7 @@ static void at_xdmac_advance_work(struct at_xdmac_chan *atchan) > at_xdmac_start_xfer(atchan, desc); > } > > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, flags); > } > > static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan) > @@ -1353,12 +1359,13 @@ static int at_xdmac_device_config(struct dma_chan *chan, > { > struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > int ret; > + unsigned long flags; > > dev_dbg(chan2dev(chan), "%s\n", __func__); > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, flags); > ret = at_xdmac_set_slave_config(chan, config); > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, flags); > > return ret; > } > @@ -1367,18 +1374,19 @@ static int at_xdmac_device_pause(struct dma_chan *chan) > { > struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); > + unsigned long flags; > > dev_dbg(chan2dev(chan), "%s\n", __func__); > > if (test_and_set_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status)) > return 0; > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, flags); > at_xdmac_write(atxdmac, AT_XDMAC_GRWS, atchan->mask); > while (at_xdmac_chan_read(atchan, AT_XDMAC_CC) > & (AT_XDMAC_CC_WRIP | AT_XDMAC_CC_RDIP)) > cpu_relax(); > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, flags); > > return 0; > } > @@ -1387,18 +1395,19 @@ static int at_xdmac_device_resume(struct dma_chan *chan) > { > struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); > + unsigned long flags; > > dev_dbg(chan2dev(chan), "%s\n", __func__); > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, flags); > if (!at_xdmac_chan_is_paused(atchan)) { > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, flags); > return 0; > } > > at_xdmac_write(atxdmac, AT_XDMAC_GRWR, atchan->mask); > clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status); > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, flags); > > return 0; > } > @@ -1408,10 +1417,11 @@ static int at_xdmac_device_terminate_all(struct dma_chan *chan) > struct at_xdmac_desc *desc, *_desc; > struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); > + unsigned long flags; > > dev_dbg(chan2dev(chan), "%s\n", __func__); > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, flags); > at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask); > while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask) > cpu_relax(); > @@ -1421,7 +1431,7 @@ static int at_xdmac_device_terminate_all(struct dma_chan *chan) > at_xdmac_remove_xfer(atchan, desc); > > clear_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status); > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, flags); > > return 0; > } > @@ -1431,8 +1441,9 @@ static int at_xdmac_alloc_chan_resources(struct dma_chan *chan) > struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > struct at_xdmac_desc *desc; > int i; > + unsigned long flags; > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, flags); > > if (at_xdmac_chan_is_enabled(atchan)) { > dev_err(chan2dev(chan), > @@ -1463,7 +1474,7 @@ static int at_xdmac_alloc_chan_resources(struct dma_chan *chan) > dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i); > > spin_unlock: > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, flags); > return i; > } > >
On Wed, Jun 03, 2015 at 04:52:26PM +0200, Ludovic Desroches wrote: > Using _bh variant for spin locks causes this kind of warning: > Starting logging: ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 3 at /ssd_drive/linux/kernel/softirq.c:151 > __local_bh_enable_ip+0xe8/0xf4() > Modules linked in: > CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.1.0-rc2+ #94 > Hardware name: Atmel SAMA5 > [<c0013c04>] (unwind_backtrace) from [<c00118a4>] (show_stack+0x10/0x14) > [<c00118a4>] (show_stack) from [<c001bbcc>] > (warn_slowpath_common+0x80/0xac) > [<c001bbcc>] (warn_slowpath_common) from [<c001bc14>] > (warn_slowpath_null+0x1c/0x24) > [<c001bc14>] (warn_slowpath_null) from [<c001e28c>] > (__local_bh_enable_ip+0xe8/0xf4) > [<c001e28c>] (__local_bh_enable_ip) from [<c01fdbd0>] > (at_xdmac_device_terminate_all+0xf4/0x100) > [<c01fdbd0>] (at_xdmac_device_terminate_all) from [<c02221a4>] > (atmel_complete_tx_dma+0x34/0xf4) > [<c02221a4>] (atmel_complete_tx_dma) from [<c01fe4ac>] > (at_xdmac_tasklet+0x14c/0x1ac) > [<c01fe4ac>] (at_xdmac_tasklet) from [<c001de58>] > (tasklet_action+0x68/0xb4) > [<c001de58>] (tasklet_action) from [<c001dfdc>] > (__do_softirq+0xfc/0x238) > [<c001dfdc>] (__do_softirq) from [<c001e140>] (run_ksoftirqd+0x28/0x34) > [<c001e140>] (run_ksoftirqd) from [<c0033a3c>] > (smpboot_thread_fn+0x138/0x18c) > [<c0033a3c>] (smpboot_thread_fn) from [<c0030e7c>] (kthread+0xdc/0xf0) > [<c0030e7c>] (kthread) from [<c000f480>] (ret_from_fork+0x14/0x34) > ---[ end trace b57b14a99c1d8812 ]--- > > It comes from the fact that devices can called some code from the DMA > controller with irq disabled. _bh variant is not intended to be used in > this case since it can enable irqs. Switch to irqsave/irqrestore variant to > avoid this situation. > > Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> > Cc: stable@vger.kernel.org # 4.0 and later > --- > drivers/dma/at_xdmac.c | 85 ++++++++++++++++++++++++++++---------------------- > 1 file changed, 48 insertions(+), 37 deletions(-) > > diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c > index 9b602a6..4a7e9c6 100644 > --- a/drivers/dma/at_xdmac.c > +++ b/drivers/dma/at_xdmac.c > @@ -421,8 +421,9 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx) > struct at_xdmac_desc *desc = txd_to_at_desc(tx); > struct at_xdmac_chan *atchan = to_at_xdmac_chan(tx->chan); > dma_cookie_t cookie; > + unsigned long irqflags; > > - spin_lock_bh(&atchan->lock); > + spin_lock_irqsave(&atchan->lock, irqflags); > cookie = dma_cookie_assign(tx); > > dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n", > @@ -431,7 +432,7 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx) > if (list_is_singular(&atchan->xfers_list)) > at_xdmac_start_xfer(atchan, desc); > > - spin_unlock_bh(&atchan->lock); > + spin_unlock_irqrestore(&atchan->lock, irqflags); > return cookie; > } > > @@ -591,11 +592,13 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, > unsigned int sg_len, enum dma_transfer_direction direction, > unsigned long flags, void *context) > { > - struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > - struct at_xdmac_desc *first = NULL, *prev = NULL; > - struct scatterlist *sg; > - int i; > - unsigned int xfer_size = 0; > + struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > + struct at_xdmac_desc *first = NULL, *prev = NULL; > + struct scatterlist *sg; > + int i; > + unsigned int xfer_size = 0; > + unsigned long irqflags; > + struct dma_async_tx_descriptor *ret = NULL; This doesnt comply with stable rules, and you should not keep this in fixes either :( - It cannot contain any "trivial" fixes in it (spelling changes, whitespace cleanups, etc).
On Thu, Jun 04, 2015 at 07:49:38PM +0530, Vinod Koul wrote: > On Wed, Jun 03, 2015 at 04:52:26PM +0200, Ludovic Desroches wrote: > > Using _bh variant for spin locks causes this kind of warning: > > Starting logging: ------------[ cut here ]------------ > > WARNING: CPU: 0 PID: 3 at /ssd_drive/linux/kernel/softirq.c:151 > > __local_bh_enable_ip+0xe8/0xf4() > > Modules linked in: > > CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.1.0-rc2+ #94 > > Hardware name: Atmel SAMA5 > > [<c0013c04>] (unwind_backtrace) from [<c00118a4>] (show_stack+0x10/0x14) > > [<c00118a4>] (show_stack) from [<c001bbcc>] > > (warn_slowpath_common+0x80/0xac) > > [<c001bbcc>] (warn_slowpath_common) from [<c001bc14>] > > (warn_slowpath_null+0x1c/0x24) > > [<c001bc14>] (warn_slowpath_null) from [<c001e28c>] > > (__local_bh_enable_ip+0xe8/0xf4) > > [<c001e28c>] (__local_bh_enable_ip) from [<c01fdbd0>] > > (at_xdmac_device_terminate_all+0xf4/0x100) > > [<c01fdbd0>] (at_xdmac_device_terminate_all) from [<c02221a4>] > > (atmel_complete_tx_dma+0x34/0xf4) > > [<c02221a4>] (atmel_complete_tx_dma) from [<c01fe4ac>] > > (at_xdmac_tasklet+0x14c/0x1ac) > > [<c01fe4ac>] (at_xdmac_tasklet) from [<c001de58>] > > (tasklet_action+0x68/0xb4) > > [<c001de58>] (tasklet_action) from [<c001dfdc>] > > (__do_softirq+0xfc/0x238) > > [<c001dfdc>] (__do_softirq) from [<c001e140>] (run_ksoftirqd+0x28/0x34) > > [<c001e140>] (run_ksoftirqd) from [<c0033a3c>] > > (smpboot_thread_fn+0x138/0x18c) > > [<c0033a3c>] (smpboot_thread_fn) from [<c0030e7c>] (kthread+0xdc/0xf0) > > [<c0030e7c>] (kthread) from [<c000f480>] (ret_from_fork+0x14/0x34) > > ---[ end trace b57b14a99c1d8812 ]--- > > > > It comes from the fact that devices can called some code from the DMA > > controller with irq disabled. _bh variant is not intended to be used in > > this case since it can enable irqs. Switch to irqsave/irqrestore variant to > > avoid this situation. > > > > Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> > > Cc: stable@vger.kernel.org # 4.0 and later > > --- > > drivers/dma/at_xdmac.c | 85 ++++++++++++++++++++++++++++---------------------- > > 1 file changed, 48 insertions(+), 37 deletions(-) > > > > diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c > > index 9b602a6..4a7e9c6 100644 > > --- a/drivers/dma/at_xdmac.c > > +++ b/drivers/dma/at_xdmac.c > > @@ -421,8 +421,9 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx) > > struct at_xdmac_desc *desc = txd_to_at_desc(tx); > > struct at_xdmac_chan *atchan = to_at_xdmac_chan(tx->chan); > > dma_cookie_t cookie; > > + unsigned long irqflags; > > > > - spin_lock_bh(&atchan->lock); > > + spin_lock_irqsave(&atchan->lock, irqflags); > > cookie = dma_cookie_assign(tx); > > > > dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n", > > @@ -431,7 +432,7 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx) > > if (list_is_singular(&atchan->xfers_list)) > > at_xdmac_start_xfer(atchan, desc); > > > > - spin_unlock_bh(&atchan->lock); > > + spin_unlock_irqrestore(&atchan->lock, irqflags); > > return cookie; > > } > > > > @@ -591,11 +592,13 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, > > unsigned int sg_len, enum dma_transfer_direction direction, > > unsigned long flags, void *context) > > { > > - struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > > - struct at_xdmac_desc *first = NULL, *prev = NULL; > > - struct scatterlist *sg; > > - int i; > > - unsigned int xfer_size = 0; > > + struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > > + struct at_xdmac_desc *first = NULL, *prev = NULL; > > + struct scatterlist *sg; > > + int i; > > + unsigned int xfer_size = 0; > > + unsigned long irqflags; > > + struct dma_async_tx_descriptor *ret = NULL; > This doesnt comply with stable rules, and you should not keep this in fixes > either :( > > - It cannot contain any "trivial" fixes in it (spelling changes, > whitespace cleanups, etc). Ok I understand, so what is the way to manage this case? I did "whitespace cleanup" because of + struct dma_async_tx_descriptor *ret = NULL; which breaks previous indentation, so in my mind it was not cleanup. Do I need to send you a patch to correct identation due to this fix or to send a specific patch for stable without identation change? Thanks Ludovic
On Thu, Jun 04, 2015 at 05:09:46PM +0200, Ludovic Desroches wrote: > > > @@ -591,11 +592,13 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, > > > unsigned int sg_len, enum dma_transfer_direction direction, > > > unsigned long flags, void *context) > > > { > > > - struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > > > - struct at_xdmac_desc *first = NULL, *prev = NULL; > > > - struct scatterlist *sg; > > > - int i; > > > - unsigned int xfer_size = 0; > > > + struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); > > > + struct at_xdmac_desc *first = NULL, *prev = NULL; > > > + struct scatterlist *sg; > > > + int i; > > > + unsigned int xfer_size = 0; > > > + unsigned long irqflags; > > > + struct dma_async_tx_descriptor *ret = NULL; > > This doesnt comply with stable rules, and you should not keep this in fixes > > either :( > > > > - It cannot contain any "trivial" fixes in it (spelling changes, > > whitespace cleanups, etc). > > Ok I understand, so what is the way to manage this case? I did > "whitespace cleanup" because of > + struct dma_async_tx_descriptor *ret = NULL; > which breaks previous indentation, so in my mind it was not cleanup. > > Do I need to send you a patch to correct identation due to this fix or to send > a specific patch for stable without identation change? I think only adding the last line should do, in whatever indentation you prefer Later on if you want to align them to whatever alignment you prefer send a follow on patch Also on 2nd patch, it looks good, but was wondering if you could split it up. This will help folks backporting the changes to stable as well Thanks
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index 9b602a6..4a7e9c6 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -421,8 +421,9 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx) struct at_xdmac_desc *desc = txd_to_at_desc(tx); struct at_xdmac_chan *atchan = to_at_xdmac_chan(tx->chan); dma_cookie_t cookie; + unsigned long irqflags; - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, irqflags); cookie = dma_cookie_assign(tx); dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n", @@ -431,7 +432,7 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx) if (list_is_singular(&atchan->xfers_list)) at_xdmac_start_xfer(atchan, desc); - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, irqflags); return cookie; } @@ -591,11 +592,13 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len, enum dma_transfer_direction direction, unsigned long flags, void *context) { - struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); - struct at_xdmac_desc *first = NULL, *prev = NULL; - struct scatterlist *sg; - int i; - unsigned int xfer_size = 0; + struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); + struct at_xdmac_desc *first = NULL, *prev = NULL; + struct scatterlist *sg; + int i; + unsigned int xfer_size = 0; + unsigned long irqflags; + struct dma_async_tx_descriptor *ret = NULL; if (!sgl) return NULL; @@ -611,7 +614,7 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, flags); /* Protect dma_sconfig field that can be modified by set_slave_conf. */ - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, irqflags); /* Prepare descriptors. */ for_each_sg(sgl, sg, sg_len, i) { @@ -622,8 +625,7 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, mem = sg_dma_address(sg); if (unlikely(!len)) { dev_err(chan2dev(chan), "sg data length is zero\n"); - spin_unlock_bh(&atchan->lock); - return NULL; + goto spin_unlock; } dev_dbg(chan2dev(chan), "%s: * sg%d len=%u, mem=0x%08x\n", __func__, i, len, mem); @@ -633,8 +635,7 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, dev_err(chan2dev(chan), "can't get descriptor\n"); if (first) list_splice_init(&first->descs_list, &atchan->free_descs_list); - spin_unlock_bh(&atchan->lock); - return NULL; + goto spin_unlock; } /* Linked list descriptor setup. */ @@ -673,13 +674,15 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, xfer_size += len; } - spin_unlock_bh(&atchan->lock); first->tx_dma_desc.flags = flags; first->xfer_size = xfer_size; first->direction = direction; + ret = &first->tx_dma_desc; - return &first->tx_dma_desc; +spin_unlock: + spin_unlock_irqrestore(&atchan->lock, irqflags); + return ret; } static struct dma_async_tx_descriptor * @@ -692,6 +695,7 @@ at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, struct at_xdmac_desc *first = NULL, *prev = NULL; unsigned int periods = buf_len / period_len; int i; + unsigned long irqflags; dev_dbg(chan2dev(chan), "%s: buf_addr=%pad, buf_len=%zd, period_len=%zd, dir=%s, flags=0x%lx\n", __func__, &buf_addr, buf_len, period_len, @@ -710,16 +714,16 @@ at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, for (i = 0; i < periods; i++) { struct at_xdmac_desc *desc = NULL; - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, irqflags); desc = at_xdmac_get_desc(atchan); if (!desc) { dev_err(chan2dev(chan), "can't get descriptor\n"); if (first) list_splice_init(&first->descs_list, &atchan->free_descs_list); - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, irqflags); return NULL; } - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, irqflags); dev_dbg(chan2dev(chan), "%s: desc=0x%p, tx_dma_desc.phys=%pad\n", __func__, desc, &desc->tx_dma_desc.phys); @@ -1036,6 +1040,7 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, | AT_XDMAC_CC_SIF(0) | AT_XDMAC_CC_MBSIZE_SIXTEEN | AT_XDMAC_CC_TYPE_MEM_TRAN; + unsigned long irqflags; dev_dbg(chan2dev(chan), "%s: src=%pad, dest=%pad, len=%zd, flags=0x%lx\n", __func__, &src, &dest, len, flags); @@ -1051,9 +1056,9 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, dev_dbg(chan2dev(chan), "%s: remaining_size=%zu\n", __func__, remaining_size); - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, irqflags); desc = at_xdmac_get_desc(atchan); - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, irqflags); if (!desc) { dev_err(chan2dev(chan), "can't get descriptor\n"); if (first) @@ -1123,6 +1128,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, int residue; u32 cur_nda, mask, value; u8 dwidth = 0; + unsigned long flags; ret = dma_cookie_status(chan, cookie, txstate); if (ret == DMA_COMPLETE) @@ -1131,7 +1137,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, if (!txstate) return ret; - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, flags); desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node); @@ -1141,8 +1147,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, */ if (!desc->active_xfer) { dma_set_residue(txstate, desc->xfer_size); - spin_unlock_bh(&atchan->lock); - return ret; + goto spin_unlock; } residue = desc->xfer_size; @@ -1173,14 +1178,14 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie, } residue += at_xdmac_chan_read(atchan, AT_XDMAC_CUBC) << dwidth; - spin_unlock_bh(&atchan->lock); - dma_set_residue(txstate, residue); dev_dbg(chan2dev(chan), "%s: desc=0x%p, tx_dma_desc.phys=%pad, tx_status=%d, cookie=%d, residue=%d\n", __func__, desc, &desc->tx_dma_desc.phys, ret, cookie, residue); +spin_unlock: + spin_unlock_irqrestore(&atchan->lock, flags); return ret; } @@ -1201,8 +1206,9 @@ static void at_xdmac_remove_xfer(struct at_xdmac_chan *atchan, static void at_xdmac_advance_work(struct at_xdmac_chan *atchan) { struct at_xdmac_desc *desc; + unsigned long flags; - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, flags); /* * If channel is enabled, do nothing, advance_work will be triggered @@ -1217,7 +1223,7 @@ static void at_xdmac_advance_work(struct at_xdmac_chan *atchan) at_xdmac_start_xfer(atchan, desc); } - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, flags); } static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan) @@ -1353,12 +1359,13 @@ static int at_xdmac_device_config(struct dma_chan *chan, { struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); int ret; + unsigned long flags; dev_dbg(chan2dev(chan), "%s\n", __func__); - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, flags); ret = at_xdmac_set_slave_config(chan, config); - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, flags); return ret; } @@ -1367,18 +1374,19 @@ static int at_xdmac_device_pause(struct dma_chan *chan) { struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); + unsigned long flags; dev_dbg(chan2dev(chan), "%s\n", __func__); if (test_and_set_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status)) return 0; - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, flags); at_xdmac_write(atxdmac, AT_XDMAC_GRWS, atchan->mask); while (at_xdmac_chan_read(atchan, AT_XDMAC_CC) & (AT_XDMAC_CC_WRIP | AT_XDMAC_CC_RDIP)) cpu_relax(); - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, flags); return 0; } @@ -1387,18 +1395,19 @@ static int at_xdmac_device_resume(struct dma_chan *chan) { struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); + unsigned long flags; dev_dbg(chan2dev(chan), "%s\n", __func__); - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, flags); if (!at_xdmac_chan_is_paused(atchan)) { - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, flags); return 0; } at_xdmac_write(atxdmac, AT_XDMAC_GRWR, atchan->mask); clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status); - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, flags); return 0; } @@ -1408,10 +1417,11 @@ static int at_xdmac_device_terminate_all(struct dma_chan *chan) struct at_xdmac_desc *desc, *_desc; struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); + unsigned long flags; dev_dbg(chan2dev(chan), "%s\n", __func__); - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, flags); at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask); while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask) cpu_relax(); @@ -1421,7 +1431,7 @@ static int at_xdmac_device_terminate_all(struct dma_chan *chan) at_xdmac_remove_xfer(atchan, desc); clear_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status); - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, flags); return 0; } @@ -1431,8 +1441,9 @@ static int at_xdmac_alloc_chan_resources(struct dma_chan *chan) struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); struct at_xdmac_desc *desc; int i; + unsigned long flags; - spin_lock_bh(&atchan->lock); + spin_lock_irqsave(&atchan->lock, flags); if (at_xdmac_chan_is_enabled(atchan)) { dev_err(chan2dev(chan), @@ -1463,7 +1474,7 @@ static int at_xdmac_alloc_chan_resources(struct dma_chan *chan) dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i); spin_unlock: - spin_unlock_bh(&atchan->lock); + spin_unlock_irqrestore(&atchan->lock, flags); return i; }
Using _bh variant for spin locks causes this kind of warning: Starting logging: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 3 at /ssd_drive/linux/kernel/softirq.c:151 __local_bh_enable_ip+0xe8/0xf4() Modules linked in: CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.1.0-rc2+ #94 Hardware name: Atmel SAMA5 [<c0013c04>] (unwind_backtrace) from [<c00118a4>] (show_stack+0x10/0x14) [<c00118a4>] (show_stack) from [<c001bbcc>] (warn_slowpath_common+0x80/0xac) [<c001bbcc>] (warn_slowpath_common) from [<c001bc14>] (warn_slowpath_null+0x1c/0x24) [<c001bc14>] (warn_slowpath_null) from [<c001e28c>] (__local_bh_enable_ip+0xe8/0xf4) [<c001e28c>] (__local_bh_enable_ip) from [<c01fdbd0>] (at_xdmac_device_terminate_all+0xf4/0x100) [<c01fdbd0>] (at_xdmac_device_terminate_all) from [<c02221a4>] (atmel_complete_tx_dma+0x34/0xf4) [<c02221a4>] (atmel_complete_tx_dma) from [<c01fe4ac>] (at_xdmac_tasklet+0x14c/0x1ac) [<c01fe4ac>] (at_xdmac_tasklet) from [<c001de58>] (tasklet_action+0x68/0xb4) [<c001de58>] (tasklet_action) from [<c001dfdc>] (__do_softirq+0xfc/0x238) [<c001dfdc>] (__do_softirq) from [<c001e140>] (run_ksoftirqd+0x28/0x34) [<c001e140>] (run_ksoftirqd) from [<c0033a3c>] (smpboot_thread_fn+0x138/0x18c) [<c0033a3c>] (smpboot_thread_fn) from [<c0030e7c>] (kthread+0xdc/0xf0) [<c0030e7c>] (kthread) from [<c000f480>] (ret_from_fork+0x14/0x34) ---[ end trace b57b14a99c1d8812 ]--- It comes from the fact that devices can called some code from the DMA controller with irq disabled. _bh variant is not intended to be used in this case since it can enable irqs. Switch to irqsave/irqrestore variant to avoid this situation. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Cc: stable@vger.kernel.org # 4.0 and later --- drivers/dma/at_xdmac.c | 85 ++++++++++++++++++++++++++++---------------------- 1 file changed, 48 insertions(+), 37 deletions(-)