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[SCSI] sym53c8xx: fixes two bugs related to chip reset

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This patch fixes two bugs pointed by James Bottomley:

 1. the if (!sym_data->io_reset).  That variable is only ever filled
    by a stack based completion.  If we find it non empty it means
    this code has been entered twice and we have a severe problem,
    so that should just become a BUG_ON(sym_data->io_reset).
 2. sym_data->io_reset should be set to NULL before the routine is
    exited otherwise the PCI recovery code could end up completing
    what will be a bogus pointer into the stack.

Big thanks to James Bottomley for help with the patch.

Signed-off-by: Krzysztof Helt <krzysztof.h1@w.pl>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
Krzysztof Helt
2008-01-11 21:50:46 +01:00
committed by James Bottomley
parent 3a0086a80a
commit d9aa3af09c
1 changed files with 7 additions and 6 deletions
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13
drivers/scsi/sym53c8xx_2/sym_glue.c
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@@ -609,22 +609,24 @@ static int sym_eh_handler(int op, char *opname, struct scsi_cmnd *cmd)
*/ */
#define WAIT_FOR_PCI_RECOVERY 35 #define WAIT_FOR_PCI_RECOVERY 35
if (pci_channel_offline(pdev)) { if (pci_channel_offline(pdev)) {
struct completion *io_reset;
int finished_reset = 0; int finished_reset = 0;
init_completion(&eh_done); init_completion(&eh_done);
spin_lock_irq(shost->host_lock); spin_lock_irq(shost->host_lock);
/* Make sure we didn't race */ /* Make sure we didn't race */
if (pci_channel_offline(pdev)) { if (pci_channel_offline(pdev)) {
if (!sym_data->io_reset) BUG_ON(sym_data->io_reset);
sym_data->io_reset = &eh_done; sym_data->io_reset = &eh_done;
io_reset = sym_data->io_reset;
} else { } else {
finished_reset = 1; finished_reset = 1;
} }
spin_unlock_irq(shost->host_lock); spin_unlock_irq(shost->host_lock);
if (!finished_reset) if (!finished_reset)
finished_reset = wait_for_completion_timeout(io_reset, finished_reset = wait_for_completion_timeout
(sym_data->io_reset,
WAIT_FOR_PCI_RECOVERY*HZ); WAIT_FOR_PCI_RECOVERY*HZ);
spin_lock_irq(shost->host_lock);
sym_data->io_reset = NULL;
spin_unlock_irq(shost->host_lock);
if (!finished_reset) if (!finished_reset)
return SCSI_FAILED; return SCSI_FAILED;
} }
@@ -1879,7 +1881,6 @@ static void sym2_io_resume(struct pci_dev *pdev)
spin_lock_irq(shost->host_lock); spin_lock_irq(shost->host_lock);
if (sym_data->io_reset) if (sym_data->io_reset)
complete_all(sym_data->io_reset); complete_all(sym_data->io_reset);
sym_data->io_reset = NULL;
spin_unlock_irq(shost->host_lock); spin_unlock_irq(shost->host_lock);
} }