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| author | Joe Eykholt <jeykholt@cisco.com> | 2009-06-15 23:22:14 -0700 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@HansenPartnership.com> | 2009-06-21 10:52:42 -0500 |
| commit | 30c9afa6cc477f6f21f8a0b36f3b81080941a0c9 (patch) | |
| tree | 863c391cc13e13d005e55096ff3436e973c06453 /drivers/scsi/hosts.c | |
| parent | 111986593561fc4c94a1fba3f3cd84476fb40b22 (diff) | |
| download | linux-30c9afa6cc477f6f21f8a0b36f3b81080941a0c9.tar.bz2 | |
fix race that can give duplicate host number
Just once, two fcoe instances got the same host number
from scsi_add_host().
Use atomic_t and atomic_inc_return() to get next host number.
Subtract 1, so that scsi_host still starts with 0.
[jejb: added comment about unusual subtraction]
Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'drivers/scsi/hosts.c')
| -rw-r--r-- | drivers/scsi/hosts.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 89d41a424b33..5fd2da494d08 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -40,7 +40,7 @@ #include "scsi_logging.h" -static int scsi_host_next_hn; /* host_no for next new host */ +static atomic_t scsi_host_next_hn; /* host_no for next new host */ static void scsi_host_cls_release(struct device *dev) @@ -333,7 +333,11 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) mutex_init(&shost->scan_mutex); - shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */ + /* + * subtract one because we increment first then return, but we need to + * know what the next host number was before increment + */ + shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1; shost->dma_channel = 0xff; /* These three are default values which can be overridden */ |