Messages in this thread Patch in this message | | | Date | Wed, 05 Jun 2013 17:18:33 +0800 | From | vaughan <> | Subject | [PATCH] sg: atomize check and set sdp->exclude in sg_open |
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Check and set sdp->exclude should be atomic when set in sg_open().
Signed-off-by: Vaughan Cao <vaughan.cao@oracle.com> --- drivers/scsi/sg.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 25b5455..0ede08f 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -245,6 +245,21 @@ static int set_exclude(Sg_device *sdp, char val) return val; }
+/* Check if we can set exclude and then set, return 1 if success */ +static int try_set_exclude(Sg_device *sdp) +{ + unsigned long flags; + + spin_lock_irqsave(&sg_open_exclusive_lock, flags); + if (sdp->exclude) { + spin_unlock_irqrestore(&sg_open_exclusive_lock, flags); + return 0; + } + sdp->exclude = 1; + spin_unlock_irqrestore(&sg_open_exclusive_lock, flags); + return 1; +} + static int sfds_list_empty(Sg_device *sdp) { unsigned long flags; @@ -303,7 +318,7 @@ sg_open(struct inode *inode, struct file *filp) goto error_out; } res = wait_event_interruptible(sdp->o_excl_wait, - ((!sfds_list_empty(sdp) || get_exclude(sdp)) ? 0 : set_exclude(sdp, 1))); + ((!sfds_list_empty(sdp) || get_exclude(sdp)) ? 0 : try_set_exclude(sdp))); if (res) { retval = res; /* -ERESTARTSYS because signal hit process */ goto error_out; -- 1.7.11.7
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