| Message ID | 20201126132952.2287996-9-bigeasy@linutronix.de (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | scsi: Remove in_interrupt() usage. | expand |
On Thu, Nov 26, 2020 at 02:29:46PM +0100, Sebastian Andrzej Siewior wrote: > From: "Ahmed S. Darwish" <a.darwish@linutronix.de> > > qla4_82xx_rom_lock() spins on a certain hardware state until it is > updated. At the end of each spin, if in_interrupt() is true, it does 20 > loops of cpu_relax(). Otherwise, it yields the CPU. > > While in_interrupt() is ill-defined and does not provide what the name > suggests, it is not needed here: qla4_82xx_rom_lock() is always called > from process context. Below is an analysis of its callers: > > - ql4_nx.c: qla4_82xx_rom_fast_read(), all process context callers: > => ql4_nx.c: qla4_82xx_pinit_from_rom(), GFP_KERNEL allocation > => ql4_nx.c: qla4_82xx_load_from_flash(), msleep() in a loop > > - ql4_nx.c: qla4_82xx_pinit_from_rom(), earlier discussed > > - ql4_nx.c: qla4_82xx_rom_lock_recovery(), bound to "isp_operations" > ->rom_lock_recovery() hook, which has one process context caller, > qla4_8xxx_device_bootstrap(), with callers: > => ql4_83xx.c: qla4_83xx_need_reset_handler(), process, msleep() > => ql4_nx.c: qla4_8xxx_device_state_handler(), multiple msleep()s > > - ql4_nx.c: qla4_82xx_read_flash_data(), has cond_resched() > > Remove the in_interrupt() check. Mark, qla4_82xx_rom_lock(), and the > ->rom_lock_recovery() hook, with "Context: task, can sleep". > > Change qla4_82xx_rom_lock() implementation to sleep 20ms, instead of a > schedule(), for each spin. This is more deterministic, and it matches > the other implementations bound to ->rom_lock_recovery(). > > Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > Cc: Nilesh Javali <njavali@marvell.com> > Cc: Manish Rangankar <mrangankar@marvell.com> > Cc: <GR-QLogic-Storage-Upstream@marvell.com> Reviewed-by: Daniel Wagner <dwagner@suse.de>
diff --git a/drivers/scsi/qla4xxx/ql4_def.h b/drivers/scsi/qla4xxx/ql4_def.h index 9210547483886..031569c496e57 100644 --- a/drivers/scsi/qla4xxx/ql4_def.h +++ b/drivers/scsi/qla4xxx/ql4_def.h @@ -437,7 +437,7 @@ struct isp_operations { int (*wr_reg_indirect) (struct scsi_qla_host *, uint32_t, uint32_t); int (*idc_lock) (struct scsi_qla_host *); /* Context: task, can sleep */ void (*idc_unlock) (struct scsi_qla_host *); - void (*rom_lock_recovery) (struct scsi_qla_host *); + void (*rom_lock_recovery) (struct scsi_qla_host *); /* Context: task, can sleep */ void (*queue_mailbox_command) (struct scsi_qla_host *, uint32_t *, int); void (*process_mailbox_interrupt) (struct scsi_qla_host *, int); }; diff --git a/drivers/scsi/qla4xxx/ql4_nx.c b/drivers/scsi/qla4xxx/ql4_nx.c index 4362d0ebe0e15..fd30fbd0d33cb 100644 --- a/drivers/scsi/qla4xxx/ql4_nx.c +++ b/drivers/scsi/qla4xxx/ql4_nx.c @@ -871,15 +871,18 @@ qla4_82xx_decode_crb_addr(unsigned long addr) static long rom_max_timeout = 100; static long qla4_82xx_rom_lock_timeout = 100; +/* + * Context: task, can_sleep + */ static int qla4_82xx_rom_lock(struct scsi_qla_host *ha) { - int i; int done = 0, timeout = 0; + might_sleep(); + while (!done) { /* acquire semaphore2 from PCI HW block */ - done = qla4_82xx_rd_32(ha, QLA82XX_PCIE_REG(PCIE_SEM2_LOCK)); if (done == 1) break; @@ -887,14 +890,7 @@ qla4_82xx_rom_lock(struct scsi_qla_host *ha) return -1; timeout++; - - /* Yield CPU */ - if (!in_interrupt()) - schedule(); - else { - for (i = 0; i < 20; i++) - cpu_relax(); /*This a nop instr on i386*/ - } + msleep(20); } qla4_82xx_wr_32(ha, QLA82XX_ROM_LOCK_ID, ROM_LOCK_DRIVER); return 0;