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authorIan Munsie <imunsie@au1.ibm.com>2014-10-09 04:17:46 +0400
committerMichael Ellerman <mpe@ellerman.id.au>2014-10-09 04:29:57 +0400
commitd53ba6b3bba33432cc37b7101a86f8f3392c46e7 (patch)
treea82fe60070c230303bc1daa7ce55384ab46904d0 /drivers/misc
parenta9282d01cf357379ce29103cec5e7651a53c634d (diff)
downloadlinux-d53ba6b3bba33432cc37b7101a86f8f3392c46e7.tar.xz
cxl: Fix afu_read() not doing finish_wait() on signal or non-blocking
If afu_read() returned due to a signal or the AFU file descriptor being opened non-blocking it would not call finish_wait() before returning, which could lead to a crash later when something else wakes up the wait queue. This patch restructures the wait logic to ensure that the cleanup is done correctly. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/cxl/file.c20
1 files changed, 15 insertions, 5 deletions
diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 847b7e646a7e..378b099e7c0b 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -273,6 +273,7 @@ static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
struct cxl_context *ctx = file->private_data;
struct cxl_event event;
unsigned long flags;
+ int rc;
DEFINE_WAIT(wait);
if (count < CXL_READ_MIN_SIZE)
@@ -285,13 +286,17 @@ static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
if (ctx_event_pending(ctx))
break;
- spin_unlock_irqrestore(&ctx->lock, flags);
- if (file->f_flags & O_NONBLOCK)
- return -EAGAIN;
+ if (file->f_flags & O_NONBLOCK) {
+ rc = -EAGAIN;
+ goto out;
+ }
- if (signal_pending(current))
- return -ERESTARTSYS;
+ if (signal_pending(current)) {
+ rc = -ERESTARTSYS;
+ goto out;
+ }
+ spin_unlock_irqrestore(&ctx->lock, flags);
pr_devel("afu_read going to sleep...\n");
schedule();
pr_devel("afu_read woken up\n");
@@ -336,6 +341,11 @@ static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
if (copy_to_user(buf, &event, event.header.size))
return -EFAULT;
return event.header.size;
+
+out:
+ finish_wait(&ctx->wq, &wait);
+ spin_unlock_irqrestore(&ctx->lock, flags);
+ return rc;
}
static const struct file_operations afu_fops = {