From b4e93a739ed1352664defd41d5e4f82afa29b928 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 28 Mar 2006 11:03:44 -0500 Subject: [PATCH] [SCSI] Simplify error handling Use wait_for_completion_timeout() instead of using a timer (as Christoph Hellwig did for aic7xxx). That lets me eliminate the sym_eh_wait structure; the struct completion, the old_done pointer and the to_do flag can be folded into the sym_ucmd (which overrides the scsi_pointer in scsi_cmnd). The sym_eh_done() function becomes much simpler as the timeout handling is done in sym_eh_handler() directly. The host_lock can be unlocked earlier, and I cache the host in a local variable to make accesses to it quicker. Signed-off-by: Matthew Wilcox Signed-off-by: James Bottomley --- drivers/scsi/sym53c8xx_2/sym_glue.c | 84 ++++++++--------------------- 1 file changed, 22 insertions(+), 62 deletions(-) diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c index a27dd66b6613..e48409e26e5f 100644 --- a/drivers/scsi/sym53c8xx_2/sym_glue.c +++ b/drivers/scsi/sym53c8xx_2/sym_glue.c @@ -136,25 +136,15 @@ static void sym2_setup_params(void) static struct scsi_transport_template *sym2_transport_template = NULL; -/* - * Used by the eh thread to wait for command completion. - * It is allocated on the eh thread stack. - */ -struct sym_eh_wait { - struct completion done; - struct timer_list timer; - void (*old_done)(struct scsi_cmnd *); - int to_do; - int timed_out; -}; - /* * Driver private area in the SCSI command structure. */ struct sym_ucmd { /* Override the SCSI pointer structure */ + struct completion done; + void (*old_done)(struct scsi_cmnd *); dma_addr_t data_mapping; - u_char data_mapped; - struct sym_eh_wait *eh_wait; + int to_do; + u_char data_mapped; /* corresponds to data_mapping above */ }; #define SYM_UCMD_PTR(cmd) ((struct sym_ucmd *)(&(cmd)->SCp)) @@ -713,40 +703,19 @@ static void sym53c8xx_timer(unsigned long npref) #define SYM_EH_DO_WAIT 2 /* - * Our general completion handler. + * scsi_done() alias when error recovery is in progress. */ -static void __sym_eh_done(struct scsi_cmnd *cmd, int timed_out) +static void sym_eh_done(struct scsi_cmnd *cmd) { - struct sym_eh_wait *ep = SYM_UCMD_PTR(cmd)->eh_wait; - if (!ep) - return; - - /* Try to avoid a race here (not 100% safe) */ - if (!timed_out) { - ep->timed_out = 0; - if (ep->to_do == SYM_EH_DO_WAIT && !del_timer(&ep->timer)) - return; - } + struct sym_ucmd *ucmd = SYM_UCMD_PTR(cmd); + BUILD_BUG_ON(sizeof(struct scsi_pointer) < sizeof(struct sym_ucmd)); - /* Revert everything */ - SYM_UCMD_PTR(cmd)->eh_wait = NULL; - cmd->scsi_done = ep->old_done; + cmd->scsi_done = ucmd->old_done; - /* Wake up the eh thread if it wants to sleep */ - if (ep->to_do == SYM_EH_DO_WAIT) - complete(&ep->done); + if (ucmd->to_do == SYM_EH_DO_WAIT) + complete(&ucmd->done); } -/* - * scsi_done() alias when error recovery is in progress. - */ -static void sym_eh_done(struct scsi_cmnd *cmd) { __sym_eh_done(cmd, 0); } - -/* - * Some timeout handler to avoid waiting too long. - */ -static void sym_eh_timeout(u_long p) { __sym_eh_done((struct scsi_cmnd *)p, 1); } - /* * Generic method for our eh processing. * The 'op' argument tells what we have to do. @@ -754,14 +723,15 @@ static void sym_eh_timeout(u_long p) { __sym_eh_done((struct scsi_cmnd *)p, 1); static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd) { struct sym_hcb *np = SYM_SOFTC_PTR(cmd); + struct sym_ucmd *ucmd = SYM_UCMD_PTR(cmd); + struct Scsi_Host *host = cmd->device->host; SYM_QUEHEAD *qp; int to_do = SYM_EH_DO_IGNORE; int sts = -1; - struct sym_eh_wait eh, *ep = &eh; dev_warn(&cmd->device->sdev_gendev, "%s operation started.\n", opname); - spin_lock_irq(cmd->device->host->host_lock); + spin_lock_irq(host->host_lock); /* This one is queued in some place -> to wait for completion */ FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) { struct sym_ccb *cp = sym_que_entry(qp, struct sym_ccb, link_ccbq); @@ -772,10 +742,9 @@ static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd) } if (to_do == SYM_EH_DO_WAIT) { - init_completion(&ep->done); - ep->old_done = cmd->scsi_done; + init_completion(&ucmd->done); + ucmd->old_done = cmd->scsi_done; cmd->scsi_done = sym_eh_done; - SYM_UCMD_PTR(cmd)->eh_wait = ep; } /* Try to proceed the operation we have been asked for */ @@ -802,28 +771,19 @@ static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd) /* On error, restore everything and cross fingers :) */ if (sts) { - SYM_UCMD_PTR(cmd)->eh_wait = NULL; - cmd->scsi_done = ep->old_done; + cmd->scsi_done = ucmd->old_done; to_do = SYM_EH_DO_IGNORE; } - ep->to_do = to_do; + ucmd->to_do = to_do; + spin_unlock_irq(host->host_lock); - /* Wait for completion with locks released, as required by kernel */ if (to_do == SYM_EH_DO_WAIT) { - init_timer(&ep->timer); - ep->timer.expires = jiffies + (5*HZ); - ep->timer.function = sym_eh_timeout; - ep->timer.data = (u_long)cmd; - ep->timed_out = 1; /* Be pessimistic for once :) */ - add_timer(&ep->timer); - spin_unlock_irq(np->s.host->host_lock); - wait_for_completion(&ep->done); - spin_lock_irq(np->s.host->host_lock); - if (ep->timed_out) + if (!wait_for_completion_timeout(&ucmd->done, 5*HZ)) { + ucmd->to_do = SYM_EH_DO_IGNORE; sts = -2; + } } - spin_unlock_irq(cmd->device->host->host_lock); dev_warn(&cmd->device->sdev_gendev, "%s operation %s.\n", opname, sts==0 ? "complete" :sts==-2 ? "timed-out" : "failed"); return sts ? SCSI_FAILED : SCSI_SUCCESS; -- 2.20.1