| Message ID | c6e6cdaca252b5364bd294093673951036488cf0.1588439073.git.cristian.ciocaltea@gmail.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | f8f482deb078389b42768b2193e050a81aae137d |
| Headers | show |
| Series | [v4,1/1] dmaengine: owl: Use correct lock in owl_dma_get_pchan() | expand |
On 02-05-20, 20:15, Cristian Ciocaltea wrote: > When the kernel is built with lockdep support and the owl-dma driver is > used, the following message is shown: > > [ 2.496939] INFO: trying to register non-static key. > [ 2.501889] the code is fine but needs lockdep annotation. > [ 2.507357] turning off the locking correctness validator. > [ 2.512834] CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.6.3+ #15 > [ 2.519084] Hardware name: Generic DT based system > [ 2.523878] Workqueue: events_freezable mmc_rescan > [ 2.528681] [<801127f0>] (unwind_backtrace) from [<8010da58>] (show_stack+0x10/0x14) > [ 2.536420] [<8010da58>] (show_stack) from [<8080fbe8>] (dump_stack+0xb4/0xe0) > [ 2.543645] [<8080fbe8>] (dump_stack) from [<8017efa4>] (register_lock_class+0x6f0/0x718) > [ 2.551816] [<8017efa4>] (register_lock_class) from [<8017b7d0>] (__lock_acquire+0x78/0x25f0) > [ 2.560330] [<8017b7d0>] (__lock_acquire) from [<8017e5e4>] (lock_acquire+0xd8/0x1f4) > [ 2.568159] [<8017e5e4>] (lock_acquire) from [<80831fb0>] (_raw_spin_lock_irqsave+0x3c/0x50) > [ 2.576589] [<80831fb0>] (_raw_spin_lock_irqsave) from [<8051b5fc>] (owl_dma_issue_pending+0xbc/0x120) > [ 2.585884] [<8051b5fc>] (owl_dma_issue_pending) from [<80668cbc>] (owl_mmc_request+0x1b0/0x390) > [ 2.594655] [<80668cbc>] (owl_mmc_request) from [<80650ce0>] (mmc_start_request+0x94/0xbc) > [ 2.602906] [<80650ce0>] (mmc_start_request) from [<80650ec0>] (mmc_wait_for_req+0x64/0xd0) > [ 2.611245] [<80650ec0>] (mmc_wait_for_req) from [<8065aa10>] (mmc_app_send_scr+0x10c/0x144) > [ 2.619669] [<8065aa10>] (mmc_app_send_scr) from [<80659b3c>] (mmc_sd_setup_card+0x4c/0x318) > [ 2.628092] [<80659b3c>] (mmc_sd_setup_card) from [<80659f0c>] (mmc_sd_init_card+0x104/0x430) > [ 2.636601] [<80659f0c>] (mmc_sd_init_card) from [<8065a3e0>] (mmc_attach_sd+0xcc/0x16c) > [ 2.644678] [<8065a3e0>] (mmc_attach_sd) from [<8065301c>] (mmc_rescan+0x3ac/0x40c) > [ 2.652332] [<8065301c>] (mmc_rescan) from [<80143244>] (process_one_work+0x2d8/0x780) > [ 2.660239] [<80143244>] (process_one_work) from [<80143730>] (worker_thread+0x44/0x598) > [ 2.668323] [<80143730>] (worker_thread) from [<8014b5f8>] (kthread+0x148/0x150) > [ 2.675708] [<8014b5f8>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20) > [ 2.682912] Exception stack(0xee8fdfb0 to 0xee8fdff8) > [ 2.687954] dfa0: 00000000 00000000 00000000 00000000 > [ 2.696118] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > [ 2.704277] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 > > The obvious fix would be to use 'spin_lock_init()' on 'pchan->lock' > before attempting to call 'spin_lock_irqsave()' in 'owl_dma_get_pchan()'. > > However, according to Manivannan Sadhasivam, 'pchan->lock' was supposed > to only protect 'pchan->vchan' while 'od->lock' does a similar job in > 'owl_dma_terminate_pchan()'. > > Therefore, this patch substitutes 'pchan->lock' with 'od->lock' and > removes the 'lock' attribute in 'owl_dma_pchan' struct. Applied, thanks
diff --git a/drivers/dma/owl-dma.c b/drivers/dma/owl-dma.c index c683051257fd..66ef70b00ec0 100644 --- a/drivers/dma/owl-dma.c +++ b/drivers/dma/owl-dma.c @@ -175,13 +175,11 @@ struct owl_dma_txd { * @id: physical index to this channel * @base: virtual memory base for the dma channel * @vchan: the virtual channel currently being served by this physical channel - * @lock: a lock to use when altering an instance of this struct */ struct owl_dma_pchan { u32 id; void __iomem *base; struct owl_dma_vchan *vchan; - spinlock_t lock; }; /** @@ -437,14 +435,14 @@ static struct owl_dma_pchan *owl_dma_get_pchan(struct owl_dma *od, for (i = 0; i < od->nr_pchans; i++) { pchan = &od->pchans[i]; - spin_lock_irqsave(&pchan->lock, flags); + spin_lock_irqsave(&od->lock, flags); if (!pchan->vchan) { pchan->vchan = vchan; - spin_unlock_irqrestore(&pchan->lock, flags); + spin_unlock_irqrestore(&od->lock, flags); break; } - spin_unlock_irqrestore(&pchan->lock, flags); + spin_unlock_irqrestore(&od->lock, flags); } return pchan;
When the kernel is built with lockdep support and the owl-dma driver is used, the following message is shown: [ 2.496939] INFO: trying to register non-static key. [ 2.501889] the code is fine but needs lockdep annotation. [ 2.507357] turning off the locking correctness validator. [ 2.512834] CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.6.3+ #15 [ 2.519084] Hardware name: Generic DT based system [ 2.523878] Workqueue: events_freezable mmc_rescan [ 2.528681] [<801127f0>] (unwind_backtrace) from [<8010da58>] (show_stack+0x10/0x14) [ 2.536420] [<8010da58>] (show_stack) from [<8080fbe8>] (dump_stack+0xb4/0xe0) [ 2.543645] [<8080fbe8>] (dump_stack) from [<8017efa4>] (register_lock_class+0x6f0/0x718) [ 2.551816] [<8017efa4>] (register_lock_class) from [<8017b7d0>] (__lock_acquire+0x78/0x25f0) [ 2.560330] [<8017b7d0>] (__lock_acquire) from [<8017e5e4>] (lock_acquire+0xd8/0x1f4) [ 2.568159] [<8017e5e4>] (lock_acquire) from [<80831fb0>] (_raw_spin_lock_irqsave+0x3c/0x50) [ 2.576589] [<80831fb0>] (_raw_spin_lock_irqsave) from [<8051b5fc>] (owl_dma_issue_pending+0xbc/0x120) [ 2.585884] [<8051b5fc>] (owl_dma_issue_pending) from [<80668cbc>] (owl_mmc_request+0x1b0/0x390) [ 2.594655] [<80668cbc>] (owl_mmc_request) from [<80650ce0>] (mmc_start_request+0x94/0xbc) [ 2.602906] [<80650ce0>] (mmc_start_request) from [<80650ec0>] (mmc_wait_for_req+0x64/0xd0) [ 2.611245] [<80650ec0>] (mmc_wait_for_req) from [<8065aa10>] (mmc_app_send_scr+0x10c/0x144) [ 2.619669] [<8065aa10>] (mmc_app_send_scr) from [<80659b3c>] (mmc_sd_setup_card+0x4c/0x318) [ 2.628092] [<80659b3c>] (mmc_sd_setup_card) from [<80659f0c>] (mmc_sd_init_card+0x104/0x430) [ 2.636601] [<80659f0c>] (mmc_sd_init_card) from [<8065a3e0>] (mmc_attach_sd+0xcc/0x16c) [ 2.644678] [<8065a3e0>] (mmc_attach_sd) from [<8065301c>] (mmc_rescan+0x3ac/0x40c) [ 2.652332] [<8065301c>] (mmc_rescan) from [<80143244>] (process_one_work+0x2d8/0x780) [ 2.660239] [<80143244>] (process_one_work) from [<80143730>] (worker_thread+0x44/0x598) [ 2.668323] [<80143730>] (worker_thread) from [<8014b5f8>] (kthread+0x148/0x150) [ 2.675708] [<8014b5f8>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20) [ 2.682912] Exception stack(0xee8fdfb0 to 0xee8fdff8) [ 2.687954] dfa0: 00000000 00000000 00000000 00000000 [ 2.696118] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 2.704277] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 The obvious fix would be to use 'spin_lock_init()' on 'pchan->lock' before attempting to call 'spin_lock_irqsave()' in 'owl_dma_get_pchan()'. However, according to Manivannan Sadhasivam, 'pchan->lock' was supposed to only protect 'pchan->vchan' while 'od->lock' does a similar job in 'owl_dma_terminate_pchan()'. Therefore, this patch substitutes 'pchan->lock' with 'od->lock' and removes the 'lock' attribute in 'owl_dma_pchan' struct. Fixes: 47e20577c24d ("dmaengine: Add Actions Semi Owl family S900 DMA driver") Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Acked-by: Andreas Färber <afaerber@suse.de> --- Changes in v4: * Change patch title from 'dma: actions: Fix lockdep splat for owl-dma' to 'dmaengine: owl: Use correct lock in owl_dma_get_pchan()' * Add Fixes and Acked-by tags in the commit message Changes in v3: * Get rid of the kerneldoc comment for the removed struct attribute * Add the Reviewed-by tag in the commit message Changes in v2: * Improve the fix as suggested by Manivannan Sadhasivam: substitute 'pchan->lock' with 'od->lock' and get rid of the 'lock' attribute in 'owl_dma_pchan' struct * Update the commit message to reflect the changes drivers/dma/owl-dma.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)