[PATCH 01/12] xen: introduce xenbus_read_unsigned()

[PATCH 01/12] xen: introduce xenbus_read_unsigned()

[Juergen Gross]

There are multiple instances of code reading an optional unsigned
parameter from Xenstore via xenbus_scanf(). Instead of repeating the
same code over and over add a service function doing the job.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/xen/xenbus/xenbus_xs.c | 15 +++++++++++++++
 include/xen/xenbus.h           |  4 ++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 22f7cd7..99dfdfa 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -559,6 +559,21 @@ int xenbus_scanf(struct xenbus_transaction t,
 }
 EXPORT_SYMBOL_GPL(xenbus_scanf);
 
+/* Read an (optional) unsigned value. */
+unsigned int xenbus_read_unsigned(const char *dir, const char *node,
+				  unsigned int default_val)
+{
+	unsigned int val;
+	int ret;
+
+	ret = xenbus_scanf(XBT_NIL, dir, node, "%u", &val);
+	if (ret <= 0)
+		val = default_val;
+
+	return val;
+}
+EXPORT_SYMBOL_GPL(xenbus_read_unsigned);
+
 /* Single printf and write: returns -errno or 0. */
 int xenbus_printf(struct xenbus_transaction t,
 		  const char *dir, const char *node, const char *fmt, ...)
diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index 32b944b..271ba62 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -151,6 +151,10 @@ __scanf(4, 5)
 int xenbus_scanf(struct xenbus_transaction t,
 		 const char *dir, const char *node, const char *fmt, ...);
 
+/* Read an (optional) unsigned value. */
+unsigned int xenbus_read_unsigned(const char *dir, const char *node,
+				  unsigned int default_val);
+
 /* Single printf and write: returns -errno or 0. */
 __printf(4, 5)
 int xenbus_printf(struct xenbus_transaction t,
-- 
2.6.6


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Re: [PATCH 01/12] xen: introduce xenbus_read_unsigned()

[David Vrabel]

On 31/10/16 16:48, Juergen Gross wrote:
> There are multiple instances of code reading an optional unsigned
> parameter from Xenstore via xenbus_scanf(). Instead of repeating the
> same code over and over add a service function doing the job.

Reviewed-by: David Vrabel <david.vrabel@citrix.com>

David

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[PATCH 02/12] xen: make use of xenbus_read_unsigned() in xen-blkback

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of one read from int to unsigned,
but this case has been wrong before: negative values are not allowed
for the modified case.

Cc: konrad.wilk@oracle.com
Cc: roger.pau@citrix.com

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/block/xen-blkback/xenbus.c | 36 ++++++++++++++----------------------
 1 file changed, 14 insertions(+), 22 deletions(-)

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 3cc6d1d..415e79b 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -533,13 +533,11 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info
 	struct xenbus_device *dev = be->dev;
 	struct xen_blkif *blkif = be->blkif;
 	int err;
-	int state = 0, discard_enable;
+	int state = 0;
 	struct block_device *bdev = be->blkif->vbd.bdev;
 	struct request_queue *q = bdev_get_queue(bdev);
 
-	err = xenbus_scanf(XBT_NIL, dev->nodename, "discard-enable", "%d",
-			   &discard_enable);
-	if (err == 1 && !discard_enable)
+	if (!xenbus_read_unsigned(dev->nodename, "discard-enable", 1))
 		return;
 
 	if (blk_queue_discard(q)) {
@@ -1039,30 +1037,24 @@ static int connect_ring(struct backend_info *be)
 		xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
 		return -ENOSYS;
 	}
-	err = xenbus_scanf(XBT_NIL, dev->otherend,
-			   "feature-persistent", "%u", &pers_grants);
-	if (err <= 0)
-		pers_grants = 0;
-
+	pers_grants = xenbus_read_unsigned(dev->otherend, "feature-persistent",
+					   0);
 	be->blkif->vbd.feature_gnt_persistent = pers_grants;
 	be->blkif->vbd.overflow_max_grants = 0;
 
 	/*
 	 * Read the number of hardware queues from frontend.
 	 */
-	err = xenbus_scanf(XBT_NIL, dev->otherend, "multi-queue-num-queues",
-			   "%u", &requested_num_queues);
-	if (err < 0) {
-		requested_num_queues = 1;
-	} else {
-		if (requested_num_queues > xenblk_max_queues
-		    || requested_num_queues == 0) {
-			/* Buggy or malicious guest. */
-			xenbus_dev_fatal(dev, err,
-					"guest requested %u queues, exceeding the maximum of %u.",
-					requested_num_queues, xenblk_max_queues);
-			return -ENOSYS;
-		}
+	requested_num_queues = xenbus_read_unsigned(dev->otherend,
+						    "multi-queue-num-queues",
+						    1);
+	if (requested_num_queues > xenblk_max_queues
+	    || requested_num_queues == 0) {
+		/* Buggy or malicious guest. */
+		xenbus_dev_fatal(dev, err,
+				"guest requested %u queues, exceeding the maximum of %u.",
+				requested_num_queues, xenblk_max_queues);
+		return -ENOSYS;
 	}
 	be->blkif->nr_rings = requested_num_queues;
 	if (xen_blkif_alloc_rings(be->blkif))
-- 
2.6.6


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[PATCH 03/12] xen: make use of xenbus_read_unsigned() in xen-blkfront

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of some reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Cc: konrad.wilk@oracle.com
Cc: roger.pau@citrix.com

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/block/xen-blkfront.c | 81 ++++++++++++++------------------------------
 1 file changed, 26 insertions(+), 55 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 9908597..2ee9646 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1758,17 +1758,13 @@ static int talk_to_blkback(struct xenbus_device *dev,
 	const char *message = NULL;
 	struct xenbus_transaction xbt;
 	int err;
-	unsigned int i, max_page_order = 0;
-	unsigned int ring_page_order = 0;
+	unsigned int i, max_page_order;
+	unsigned int ring_page_order;
 
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "max-ring-page-order", "%u", &max_page_order);
-	if (err != 1)
-		info->nr_ring_pages = 1;
-	else {
-		ring_page_order = min(xen_blkif_max_ring_order, max_page_order);
-		info->nr_ring_pages = 1 << ring_page_order;
-	}
+	max_page_order = xenbus_read_unsigned(info->xbdev->otherend,
+					      "max-ring-page-order", 0);
+	ring_page_order = min(xen_blkif_max_ring_order, max_page_order);
+	info->nr_ring_pages = 1 << ring_page_order;
 
 	for (i = 0; i < info->nr_rings; i++) {
 		struct blkfront_ring_info *rinfo = &info->rinfo[i];
@@ -1877,18 +1873,14 @@ static int talk_to_blkback(struct xenbus_device *dev,
 
 static int negotiate_mq(struct blkfront_info *info)
 {
-	unsigned int backend_max_queues = 0;
-	int err;
+	unsigned int backend_max_queues;
 	unsigned int i;
 
 	BUG_ON(info->nr_rings);
 
 	/* Check if backend supports multiple queues. */
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "multi-queue-max-queues", "%u", &backend_max_queues);
-	if (err < 0)
-		backend_max_queues = 1;
-
+	backend_max_queues = xenbus_read_unsigned(info->xbdev->otherend,
+						  "multi-queue-max-queues", 1);
 	info->nr_rings = min(backend_max_queues, xen_blkif_max_queues);
 	/* We need at least one ring. */
 	if (!info->nr_rings)
@@ -2195,7 +2187,6 @@ static void blkfront_setup_discard(struct blkfront_info *info)
 	int err;
 	unsigned int discard_granularity;
 	unsigned int discard_alignment;
-	unsigned int discard_secure;
 
 	info->feature_discard = 1;
 	err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
@@ -2206,10 +2197,9 @@ static void blkfront_setup_discard(struct blkfront_info *info)
 		info->discard_granularity = discard_granularity;
 		info->discard_alignment = discard_alignment;
 	}
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "discard-secure", "%u", &discard_secure);
-	if (err > 0)
-		info->feature_secdiscard = !!discard_secure;
+	info->feature_secdiscard =
+		!!xenbus_read_unsigned(info->xbdev->otherend, "discard-secure",
+				       0);
 }
 
 static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
@@ -2301,16 +2291,11 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
  */
 static void blkfront_gather_backend_features(struct blkfront_info *info)
 {
-	int err;
-	int barrier, flush, discard, persistent;
 	unsigned int indirect_segments;
 
 	info->feature_flush = 0;
 	info->feature_fua = 0;
 
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "feature-barrier", "%d", &barrier);
-
 	/*
 	 * If there's no "feature-barrier" defined, then it means
 	 * we're dealing with a very old backend which writes
@@ -2318,7 +2303,7 @@ static void blkfront_gather_backend_features(struct blkfront_info *info)
 	 *
 	 * If there are barriers, then we use flush.
 	 */
-	if (err > 0 && barrier) {
+	if (xenbus_read_unsigned(info->xbdev->otherend, "feature-barrier", 0)) {
 		info->feature_flush = 1;
 		info->feature_fua = 1;
 	}
@@ -2327,35 +2312,23 @@ static void blkfront_gather_backend_features(struct blkfront_info *info)
 	 * And if there is "feature-flush-cache" use that above
 	 * barriers.
 	 */
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "feature-flush-cache", "%d", &flush);
-
-	if (err > 0 && flush) {
+	if (xenbus_read_unsigned(info->xbdev->otherend, "feature-flush-cache",
+				 0)) {
 		info->feature_flush = 1;
 		info->feature_fua = 0;
 	}
 
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "feature-discard", "%d", &discard);
-
-	if (err > 0 && discard)
+	if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0))
 		blkfront_setup_discard(info);
 
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "feature-persistent", "%d", &persistent);
-	if (err <= 0)
-		info->feature_persistent = 0;
-	else
-		info->feature_persistent = persistent;
+	info->feature_persistent =
+		xenbus_read_unsigned(info->xbdev->otherend,
+				     "feature-persistent", 0);
 
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "feature-max-indirect-segments", "%u",
-			   &indirect_segments);
-	if (err <= 0)
-		info->max_indirect_segments = 0;
-	else
-		info->max_indirect_segments = min(indirect_segments,
-						  xen_blkif_max_segments);
+	indirect_segments = xenbus_read_unsigned(info->xbdev->otherend,
+					"feature-max-indirect-segments", 0);
+	info->max_indirect_segments = min(indirect_segments,
+					  xen_blkif_max_segments);
 }
 
 /*
@@ -2420,11 +2393,9 @@ static void blkfront_connect(struct blkfront_info *info)
 	 * provide this. Assume physical sector size to be the same as
 	 * sector_size in that case.
 	 */
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "physical-sector-size", "%u", &physical_sector_size);
-	if (err != 1)
-		physical_sector_size = sector_size;
-
+	physical_sector_size = xenbus_read_unsigned(info->xbdev->otherend,
+						    "physical-sector-size",
+						    sector_size);
 	blkfront_gather_backend_features(info);
 	for (i = 0; i < info->nr_rings; i++) {
 		err = blkfront_setup_indirect(&info->rinfo[i]);
-- 
2.6.6


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[PATCH 04/12] xen: make use of xenbus_read_unsigned() in xen-tpmfront

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of one read from int to unsigned,
but this case has been wrong before: negative values are not allowed
for the modified case.

Cc: peterhuewe@gmx.de
Cc: tpmdd@selhorst.net
Cc: jarkko.sakkinen@linux.intel.com
Cc: jgunthorpe@obsidianresearch.com
Cc: tpmdd-devel@lists.sourceforge.net

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/char/tpm/xen-tpmfront.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/char/tpm/xen-tpmfront.c b/drivers/char/tpm/xen-tpmfront.c
index 62028f4..50072cc 100644
--- a/drivers/char/tpm/xen-tpmfront.c
+++ b/drivers/char/tpm/xen-tpmfront.c
@@ -337,18 +337,14 @@ static int tpmfront_resume(struct xenbus_device *dev)
 static void backend_changed(struct xenbus_device *dev,
 		enum xenbus_state backend_state)
 {
-	int val;
-
 	switch (backend_state) {
 	case XenbusStateInitialised:
 	case XenbusStateConnected:
 		if (dev->state == XenbusStateConnected)
 			break;
 
-		if (xenbus_scanf(XBT_NIL, dev->otherend,
-				"feature-protocol-v2", "%d", &val) < 0)
-			val = 0;
-		if (!val) {
+		if (!xenbus_read_unsigned(dev->otherend, "feature-protocol-v2",
+					  0)) {
 			xenbus_dev_fatal(dev, -EINVAL,
 					"vTPM protocol 2 required");
 			return;
-- 
2.6.6


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Re: [PATCH 04/12] xen: make use of xenbus_read_unsigned() in xen-tpmfront

[Jarkko Sakkinen]

On Mon, Oct 31, 2016 at 05:48:22PM +0100, Juergen Gross wrote:
> Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
> This requires to change the type of one read from int to unsigned,
> but this case has been wrong before: negative values are not allowed
> for the modified case.
> 
> Cc: peterhuewe@gmx.de
> Cc: tpmdd@selhorst.net
> Cc: jarkko.sakkinen@linux.intel.com
> Cc: jgunthorpe@obsidianresearch.com
> Cc: tpmdd-devel@lists.sourceforge.net
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

> ---
>  drivers/char/tpm/xen-tpmfront.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/char/tpm/xen-tpmfront.c b/drivers/char/tpm/xen-tpmfront.c
> index 62028f4..50072cc 100644
> --- a/drivers/char/tpm/xen-tpmfront.c
> +++ b/drivers/char/tpm/xen-tpmfront.c
> @@ -337,18 +337,14 @@ static int tpmfront_resume(struct xenbus_device *dev)
>  static void backend_changed(struct xenbus_device *dev,
>  		enum xenbus_state backend_state)
>  {
> -	int val;
> -
>  	switch (backend_state) {
>  	case XenbusStateInitialised:
>  	case XenbusStateConnected:
>  		if (dev->state == XenbusStateConnected)
>  			break;
>  
> -		if (xenbus_scanf(XBT_NIL, dev->otherend,
> -				"feature-protocol-v2", "%d", &val) < 0)
> -			val = 0;
> -		if (!val) {
> +		if (!xenbus_read_unsigned(dev->otherend, "feature-protocol-v2",
> +					  0)) {
>  			xenbus_dev_fatal(dev, -EINVAL,
>  					"vTPM protocol 2 required");
>  			return;
> -- 
> 2.6.6
> 

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Re: [PATCH 04/12] xen: make use of xenbus_read_unsigned() in xen-tpmfront

[Jarkko Sakkinen]

On Mon, Oct 31, 2016 at 05:48:22PM +0100, Juergen Gross wrote:
> Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
> This requires to change the type of one read from int to unsigned,
> but this case has been wrong before: negative values are not allowed
> for the modified case.
> 
> Cc: peterhuewe@gmx.de
> Cc: tpmdd@selhorst.net
> Cc: jarkko.sakkinen@linux.intel.com
> Cc: jgunthorpe@obsidianresearch.com
> Cc: tpmdd-devel@lists.sourceforge.net
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

> ---
>  drivers/char/tpm/xen-tpmfront.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/char/tpm/xen-tpmfront.c b/drivers/char/tpm/xen-tpmfront.c
> index 62028f4..50072cc 100644
> --- a/drivers/char/tpm/xen-tpmfront.c
> +++ b/drivers/char/tpm/xen-tpmfront.c
> @@ -337,18 +337,14 @@ static int tpmfront_resume(struct xenbus_device *dev)
>  static void backend_changed(struct xenbus_device *dev,
>  		enum xenbus_state backend_state)
>  {
> -	int val;
> -
>  	switch (backend_state) {
>  	case XenbusStateInitialised:
>  	case XenbusStateConnected:
>  		if (dev->state == XenbusStateConnected)
>  			break;
>  
> -		if (xenbus_scanf(XBT_NIL, dev->otherend,
> -				"feature-protocol-v2", "%d", &val) < 0)
> -			val = 0;
> -		if (!val) {
> +		if (!xenbus_read_unsigned(dev->otherend, "feature-protocol-v2",
> +					  0)) {
>  			xenbus_dev_fatal(dev, -EINVAL,
>  					"vTPM protocol 2 required");
>  			return;
> -- 
> 2.6.6
> 

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[PATCH 05/12] xen: make use of xenbus_read_unsigned() in xen-kbdfront

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of the reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Cc: dmitry.torokhov@gmail.com
Cc: linux-input@vger.kernel.org

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/input/misc/xen-kbdfront.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
index 227fbd2..3900875 100644
--- a/drivers/input/misc/xen-kbdfront.c
+++ b/drivers/input/misc/xen-kbdfront.c
@@ -108,7 +108,8 @@ static irqreturn_t input_handler(int rq, void *dev_id)
 static int xenkbd_probe(struct xenbus_device *dev,
 				  const struct xenbus_device_id *id)
 {
-	int ret, i, abs;
+	int ret, i;
+	unsigned int abs;
 	struct xenkbd_info *info;
 	struct input_dev *kbd, *ptr;
 
@@ -127,8 +128,7 @@ static int xenkbd_probe(struct xenbus_device *dev,
 	if (!info->page)
 		goto error_nomem;
 
-	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-abs-pointer", "%d", &abs) < 0)
-		abs = 0;
+	abs = xenbus_read_unsigned(dev->otherend, "feature-abs-pointer", 0);
 	if (abs) {
 		ret = xenbus_write(XBT_NIL, dev->nodename,
 				   "request-abs-pointer", "1");
@@ -322,11 +322,8 @@ static void xenkbd_backend_changed(struct xenbus_device *dev,
 
 	case XenbusStateInitWait:
 InitWait:
-		ret = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-				   "feature-abs-pointer", "%d", &val);
-		if (ret < 0)
-			val = 0;
-		if (val) {
+		if (xenbus_read_unsigned(info->xbdev->otherend,
+					 "feature-abs-pointer", 0)) {
 			ret = xenbus_write(XBT_NIL, info->xbdev->nodename,
 					   "request-abs-pointer", "1");
 			if (ret)
-- 
2.6.6


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[PATCH 06/12] xen: make use of xenbus_read_unsigned() in xen-netback

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of some reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Cc: wei.liu2@citrix.com
Cc: paul.durrant@citrix.com
Cc: netdev@vger.kernel.org

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/net/xen-netback/xenbus.c | 50 +++++++++++-----------------------------
 1 file changed, 14 insertions(+), 36 deletions(-)

diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 8674e18..7356e00 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -785,12 +785,9 @@ static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
 	struct xenvif *vif = container_of(watch, struct xenvif,
 					  mcast_ctrl_watch);
 	struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
-	int val;
 
-	if (xenbus_scanf(XBT_NIL, dev->otherend,
-			 "request-multicast-control", "%d", &val) < 0)
-		val = 0;
-	vif->multicast_control = !!val;
+	vif->multicast_control = !!xenbus_read_unsigned(dev->otherend,
+					"request-multicast-control", 0);
 }
 
 static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
@@ -934,12 +931,9 @@ static void connect(struct backend_info *be)
 	/* Check whether the frontend requested multiple queues
 	 * and read the number requested.
 	 */
-	err = xenbus_scanf(XBT_NIL, dev->otherend,
-			   "multi-queue-num-queues",
-			   "%u", &requested_num_queues);
-	if (err < 0) {
-		requested_num_queues = 1; /* Fall back to single queue */
-	} else if (requested_num_queues > xenvif_max_queues) {
+	requested_num_queues = xenbus_read_unsigned(dev->otherend,
+					"multi-queue-num-queues", 1);
+	if (requested_num_queues > xenvif_max_queues) {
 		/* buggy or malicious guest */
 		xenbus_dev_fatal(dev, err,
 				 "guest requested %u queues, exceeding the maximum of %u.",
@@ -1134,7 +1128,7 @@ static int read_xenbus_vif_flags(struct backend_info *be)
 	struct xenvif *vif = be->vif;
 	struct xenbus_device *dev = be->dev;
 	unsigned int rx_copy;
-	int err, val;
+	int err;
 
 	err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
 			   &rx_copy);
@@ -1150,10 +1144,7 @@ static int read_xenbus_vif_flags(struct backend_info *be)
 	if (!rx_copy)
 		return -EOPNOTSUPP;
 
-	if (xenbus_scanf(XBT_NIL, dev->otherend,
-			 "feature-rx-notify", "%d", &val) < 0)
-		val = 0;
-	if (!val) {
+	if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) {
 		/* - Reduce drain timeout to poll more frequently for
 		 *   Rx requests.
 		 * - Disable Rx stall detection.
@@ -1162,34 +1153,21 @@ static int read_xenbus_vif_flags(struct backend_info *be)
 		be->vif->stall_timeout = 0;
 	}
 
-	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
-			 "%d", &val) < 0)
-		val = 0;
-	vif->can_sg = !!val;
+	vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-sg", 0);
 
 	vif->gso_mask = 0;
 
-	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
-			 "%d", &val) < 0)
-		val = 0;
-	if (val)
+	if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0))
 		vif->gso_mask |= GSO_BIT(TCPV4);
 
-	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6",
-			 "%d", &val) < 0)
-		val = 0;
-	if (val)
+	if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0))
 		vif->gso_mask |= GSO_BIT(TCPV6);
 
-	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
-			 "%d", &val) < 0)
-		val = 0;
-	vif->ip_csum = !val;
+	vif->ip_csum = !xenbus_read_unsigned(dev->otherend,
+					     "feature-no-csum-offload", 0);
 
-	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload",
-			 "%d", &val) < 0)
-		val = 0;
-	vif->ipv6_csum = !!val;
+	vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
+						"feature-ipv6-csum-offload", 0);
 
 	return 0;
 }
-- 
2.6.6


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[PATCH 07/12] xen: make use of xenbus_read_unsigned() in xen-netfront

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of some reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Cc: netdev@vger.kernel.org

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/net/xen-netfront.c | 67 +++++++++++++---------------------------------
 1 file changed, 18 insertions(+), 49 deletions(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index e17879d..95d664e 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1169,43 +1169,23 @@ static netdev_features_t xennet_fix_features(struct net_device *dev,
 	netdev_features_t features)
 {
 	struct netfront_info *np = netdev_priv(dev);
-	int val;
 
-	if (features & NETIF_F_SG) {
-		if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
-				 "%d", &val) < 0)
-			val = 0;
+	if (features & NETIF_F_SG &&
+	    !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0))
+		features &= ~NETIF_F_SG;
 
-		if (!val)
-			features &= ~NETIF_F_SG;
-	}
+	if (features & NETIF_F_IPV6_CSUM &&
+	    !xenbus_read_unsigned(np->xbdev->otherend,
+				  "feature-ipv6-csum-offload", 0))
+		features &= ~NETIF_F_IPV6_CSUM;
 
-	if (features & NETIF_F_IPV6_CSUM) {
-		if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
-				 "feature-ipv6-csum-offload", "%d", &val) < 0)
-			val = 0;
+	if (features & NETIF_F_TSO &&
+	    !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0))
+		features &= ~NETIF_F_TSO;
 
-		if (!val)
-			features &= ~NETIF_F_IPV6_CSUM;
-	}
-
-	if (features & NETIF_F_TSO) {
-		if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
-				 "feature-gso-tcpv4", "%d", &val) < 0)
-			val = 0;
-
-		if (!val)
-			features &= ~NETIF_F_TSO;
-	}
-
-	if (features & NETIF_F_TSO6) {
-		if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
-				 "feature-gso-tcpv6", "%d", &val) < 0)
-			val = 0;
-
-		if (!val)
-			features &= ~NETIF_F_TSO6;
-	}
+	if (features & NETIF_F_TSO6 &&
+	    !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0))
+		features &= ~NETIF_F_TSO6;
 
 	return features;
 }
@@ -1821,18 +1801,13 @@ static int talk_to_netback(struct xenbus_device *dev,
 	info->netdev->irq = 0;
 
 	/* Check if backend supports multiple queues */
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "multi-queue-max-queues", "%u", &max_queues);
-	if (err < 0)
-		max_queues = 1;
+	max_queues = xenbus_read_unsigned(info->xbdev->otherend,
+					  "multi-queue-max-queues", 1);
 	num_queues = min(max_queues, xennet_max_queues);
 
 	/* Check feature-split-event-channels */
-	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-			   "feature-split-event-channels", "%u",
-			   &feature_split_evtchn);
-	if (err < 0)
-		feature_split_evtchn = 0;
+	feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend,
+					"feature-split-event-channels", 0);
 
 	/* Read mac addr. */
 	err = xen_net_read_mac(dev, info->netdev->dev_addr);
@@ -1966,16 +1941,10 @@ static int xennet_connect(struct net_device *dev)
 	struct netfront_info *np = netdev_priv(dev);
 	unsigned int num_queues = 0;
 	int err;
-	unsigned int feature_rx_copy;
 	unsigned int j = 0;
 	struct netfront_queue *queue = NULL;
 
-	err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
-			   "feature-rx-copy", "%u", &feature_rx_copy);
-	if (err != 1)
-		feature_rx_copy = 0;
-
-	if (!feature_rx_copy) {
+	if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) {
 		dev_info(&dev->dev,
 			 "backend does not support copying receive path\n");
 		return -ENODEV;
-- 
2.6.6


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[PATCH 08/12] xen: make use of xenbus_read_unsigned() in xen-pcifront

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of the read from int to unsigned,
but this case has been wrong before: negative values are not allowed
for the modified case.

Cc: bhelgaas@google.com
Cc: linux-pci@vger.kernel.org

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/pci/xen-pcifront.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index d6ff5e8..8fc2e95 100644
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -1038,10 +1038,8 @@ static int pcifront_detach_devices(struct pcifront_device *pdev)
 			err = -ENOMEM;
 			goto out;
 		}
-		err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%d",
-				   &state);
-		if (err != 1)
-			state = XenbusStateUnknown;
+		state = xenbus_read_unsigned(pdev->xdev->otherend, str,
+					     XenbusStateUnknown);
 
 		if (state != XenbusStateClosing)
 			continue;
-- 
2.6.6


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[PATCH 09/12] xen: make use of xenbus_read_unsigned() in xen-scsifront

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/scsi/xen-scsifront.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
index 9dc8687..7e817c6 100644
--- a/drivers/scsi/xen-scsifront.c
+++ b/drivers/scsi/xen-scsifront.c
@@ -1060,13 +1060,9 @@ static void scsifront_read_backend_params(struct xenbus_device *dev,
 					  struct vscsifrnt_info *info)
 {
 	unsigned int sg_grant, nr_segs;
-	int ret;
 	struct Scsi_Host *host = info->host;
 
-	ret = xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg-grant", "%u",
-			   &sg_grant);
-	if (ret != 1)
-		sg_grant = 0;
+	sg_grant = xenbus_read_unsigned(dev->otherend, "feature-sg-grant", 0);
 	nr_segs = min_t(unsigned int, sg_grant, SG_ALL);
 	nr_segs = max_t(unsigned int, nr_segs, VSCSIIF_SG_TABLESIZE);
 	nr_segs = min_t(unsigned int, nr_segs,
-- 
2.6.6


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[PATCH 10/12] xen: make use of xenbus_read_unsigned() in xen-fbfront

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of the reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Cc: tomi.valkeinen@ti.com
Cc: linux-fbdev@vger.kernel.org

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/video/fbdev/xen-fbfront.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/video/fbdev/xen-fbfront.c b/drivers/video/fbdev/xen-fbfront.c
index 0567d51..d0115a7 100644
--- a/drivers/video/fbdev/xen-fbfront.c
+++ b/drivers/video/fbdev/xen-fbfront.c
@@ -633,7 +633,6 @@ static void xenfb_backend_changed(struct xenbus_device *dev,
 				  enum xenbus_state backend_state)
 {
 	struct xenfb_info *info = dev_get_drvdata(&dev->dev);
-	int val;
 
 	switch (backend_state) {
 	case XenbusStateInitialising:
@@ -657,16 +656,12 @@ static void xenfb_backend_changed(struct xenbus_device *dev,
 		if (dev->state != XenbusStateConnected)
 			goto InitWait; /* no InitWait seen yet, fudge it */
 
-		if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
-				 "request-update", "%d", &val) < 0)
-			val = 0;
-		if (val)
+		if (xenbus_read_unsigned(info->xbdev->otherend,
+					 "request-update", 0))
 			info->update_wanted = 1;
 
-		if (xenbus_scanf(XBT_NIL, dev->otherend,
-				 "feature-resize", "%d", &val) < 0)
-			val = 0;
-		info->feature_resize = val;
+		info->feature_resize = xenbus_read_unsigned(dev->otherend,
+							"feature-resize", 0);
 		break;
 
 	case XenbusStateClosed:
-- 
2.6.6


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[PATCH 11/12] xen: make use of xenbus_read_unsigned() in xen-pciback

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of the read from int to unsigned,
but this case has been wrong before: negative values are not allowed
for the modified case.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/xen/xen-pciback/xenbus.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index 5ce878c..3f0aee0 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -362,7 +362,7 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
 	int err = 0;
 	int num_devs;
 	int domain, bus, slot, func;
-	int substate;
+	unsigned int substate;
 	int i, len;
 	char state_str[64];
 	char dev_str[64];
@@ -395,10 +395,8 @@ static int xen_pcibk_reconfigure(struct xen_pcibk_device *pdev)
 					 "configuration");
 			goto out;
 		}
-		err = xenbus_scanf(XBT_NIL, pdev->xdev->nodename, state_str,
-				   "%d", &substate);
-		if (err != 1)
-			substate = XenbusStateUnknown;
+		substate = xenbus_read_unsigned(pdev->xdev->nodename, state_str,
+						XenbusStateUnknown);
 
 		switch (substate) {
 		case XenbusStateInitialising:
-- 
2.6.6


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[PATCH 12/12] xen: make use of xenbus_read_unsigned() in xenbus

[Juergen Gross]

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of the reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/xen/xenbus/xenbus_probe_backend.c | 8 +-------
 drivers/xen/xenbus/xenbus_xs.c            | 7 +++----
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
index 04f7f85..37929df 100644
--- a/drivers/xen/xenbus/xenbus_probe_backend.c
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -224,13 +224,7 @@ static int read_frontend_details(struct xenbus_device *xendev)
 
 int xenbus_dev_is_online(struct xenbus_device *dev)
 {
-	int rc, val;
-
-	rc = xenbus_scanf(XBT_NIL, dev->nodename, "online", "%d", &val);
-	if (rc != 1)
-		val = 0; /* no online node present */
-
-	return val;
+	return !!xenbus_read_unsigned(dev->nodename, "online", 0);
 }
 EXPORT_SYMBOL_GPL(xenbus_dev_is_online);
 
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 99dfdfa..6afb993 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -687,7 +687,7 @@ static bool xen_strict_xenbus_quirk(void)
 }
 static void xs_reset_watches(void)
 {
-	int err, supported = 0;
+	int err;
 
 	if (!xen_hvm_domain() || xen_initial_domain())
 		return;
@@ -695,9 +695,8 @@ static void xs_reset_watches(void)
 	if (xen_strict_xenbus_quirk())
 		return;
 
-	err = xenbus_scanf(XBT_NIL, "control",
-			"platform-feature-xs_reset_watches", "%d", &supported);
-	if (err != 1 || !supported)
+	if (!xenbus_read_unsigned("control",
+				  "platform-feature-xs_reset_watches", 0))
 		return;
 
 	err = xs_error(xs_single(XBT_NIL, XS_RESET_WATCHES, "", NULL));
-- 
2.6.6


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Re: [PATCH 00/12] xen: add common function for reading optional value

[David Miller]

From: Juergen Gross <jgross@suse.com>
Date: Mon, 31 Oct 2016 17:48:18 +0100

> There are multiple instances of code reading an optional unsigned
> parameter from Xenstore via xenbus_scanf(). Instead of repeating the
> same code over and over add a service function doing the job and
> replace the call of xenbus_scanf() with the call of the new function
> where appropriate.

As this seems to be a series that will go through some tree other
than mine, I assume the networking bits will be taken care of that
way.

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Re: [PATCH 00/12] xen: add common function for reading optional value

[Juergen Gross]

On 31/10/16 18:08, David Miller wrote:
> From: Juergen Gross <jgross@suse.com>
> Date: Mon, 31 Oct 2016 17:48:18 +0100
> 
>> There are multiple instances of code reading an optional unsigned
>> parameter from Xenstore via xenbus_scanf(). Instead of repeating the
>> same code over and over add a service function doing the job and
>> replace the call of xenbus_scanf() with the call of the new function
>> where appropriate.
> 
> As this seems to be a series that will go through some tree other
> than mine, I assume the networking bits will be taken care of that
> way.
> 

If accepted I expect this series to go through the Xen tree.


Juergen

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Re: [PATCH 08/12] xen: make use of xenbus_read_unsigned() in xen-pcifront

[Bjorn Helgaas]

On Mon, Oct 31, 2016 at 05:48:26PM +0100, Juergen Gross wrote:
> Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
> This requires to change the type of the read from int to unsigned,
> but this case has been wrong before: negative values are not allowed
> for the modified case.
> 
> Cc: bhelgaas@google.com
> Cc: linux-pci@vger.kernel.org
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

I assume this will be merged with the rest of the series via some tree
other than mine.

> ---
>  drivers/pci/xen-pcifront.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
> index d6ff5e8..8fc2e95 100644
> --- a/drivers/pci/xen-pcifront.c
> +++ b/drivers/pci/xen-pcifront.c
> @@ -1038,10 +1038,8 @@ static int pcifront_detach_devices(struct pcifront_device *pdev)
>  			err = -ENOMEM;
>  			goto out;
>  		}
> -		err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%d",
> -				   &state);
> -		if (err != 1)
> -			state = XenbusStateUnknown;
> +		state = xenbus_read_unsigned(pdev->xdev->otherend, str,
> +					     XenbusStateUnknown);
>  
>  		if (state != XenbusStateClosing)
>  			continue;
> -- 
> 2.6.6
> 

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Re: [PATCH 06/12] xen: make use of xenbus_read_unsigned() in xen-netback

[Paul Durrant]

> -----Original Message-----
> From: Juergen Gross [mailto:jgross@suse.com]
> Sent: 31 October 2016 16:48
> To: linux-kernel@vger.kernel.org; xen-devel@lists.xen.org
> Cc: David Vrabel <david.vrabel@citrix.com>; boris.ostrovsky@oracle.com;
> Juergen Gross <jgross@suse.com>; Wei Liu <wei.liu2@citrix.com>; Paul
> Durrant <Paul.Durrant@citrix.com>; netdev@vger.kernel.org
> Subject: [PATCH 06/12] xen: make use of xenbus_read_unsigned() in xen-
> netback
> 
> Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
> This requires to change the type of some reads from int to unsigned,
> but these cases have been wrong before: negative values are not allowed
> for the modified cases.
> 
> Cc: wei.liu2@citrix.com
> Cc: paul.durrant@citrix.com

Reviewed-by: Paul Durrant <paul.durrant@citrix.com>

> Cc: netdev@vger.kernel.org
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
>  drivers/net/xen-netback/xenbus.c | 50 +++++++++++---------------------------
> --
>  1 file changed, 14 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-
> netback/xenbus.c
> index 8674e18..7356e00 100644
> --- a/drivers/net/xen-netback/xenbus.c
> +++ b/drivers/net/xen-netback/xenbus.c
> @@ -785,12 +785,9 @@ static void xen_mcast_ctrl_changed(struct
> xenbus_watch *watch,
>  	struct xenvif *vif = container_of(watch, struct xenvif,
>  					  mcast_ctrl_watch);
>  	struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
> -	int val;
> 
> -	if (xenbus_scanf(XBT_NIL, dev->otherend,
> -			 "request-multicast-control", "%d", &val) < 0)
> -		val = 0;
> -	vif->multicast_control = !!val;
> +	vif->multicast_control = !!xenbus_read_unsigned(dev->otherend,
> +					"request-multicast-control", 0);
>  }
> 
>  static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
> @@ -934,12 +931,9 @@ static void connect(struct backend_info *be)
>  	/* Check whether the frontend requested multiple queues
>  	 * and read the number requested.
>  	 */
> -	err = xenbus_scanf(XBT_NIL, dev->otherend,
> -			   "multi-queue-num-queues",
> -			   "%u", &requested_num_queues);
> -	if (err < 0) {
> -		requested_num_queues = 1; /* Fall back to single queue */
> -	} else if (requested_num_queues > xenvif_max_queues) {
> +	requested_num_queues = xenbus_read_unsigned(dev->otherend,
> +					"multi-queue-num-queues", 1);
> +	if (requested_num_queues > xenvif_max_queues) {
>  		/* buggy or malicious guest */
>  		xenbus_dev_fatal(dev, err,
>  				 "guest requested %u queues, exceeding the
> maximum of %u.",
> @@ -1134,7 +1128,7 @@ static int read_xenbus_vif_flags(struct
> backend_info *be)
>  	struct xenvif *vif = be->vif;
>  	struct xenbus_device *dev = be->dev;
>  	unsigned int rx_copy;
> -	int err, val;
> +	int err;
> 
>  	err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy",
> "%u",
>  			   &rx_copy);
> @@ -1150,10 +1144,7 @@ static int read_xenbus_vif_flags(struct
> backend_info *be)
>  	if (!rx_copy)
>  		return -EOPNOTSUPP;
> 
> -	if (xenbus_scanf(XBT_NIL, dev->otherend,
> -			 "feature-rx-notify", "%d", &val) < 0)
> -		val = 0;
> -	if (!val) {
> +	if (!xenbus_read_unsigned(dev->otherend, "feature-rx-notify", 0)) {
>  		/* - Reduce drain timeout to poll more frequently for
>  		 *   Rx requests.
>  		 * - Disable Rx stall detection.
> @@ -1162,34 +1153,21 @@ static int read_xenbus_vif_flags(struct
> backend_info *be)
>  		be->vif->stall_timeout = 0;
>  	}
> 
> -	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
> -			 "%d", &val) < 0)
> -		val = 0;
> -	vif->can_sg = !!val;
> +	vif->can_sg = !!xenbus_read_unsigned(dev->otherend, "feature-
> sg", 0);
> 
>  	vif->gso_mask = 0;
> 
> -	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
> -			 "%d", &val) < 0)
> -		val = 0;
> -	if (val)
> +	if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv4", 0))
>  		vif->gso_mask |= GSO_BIT(TCPV4);
> 
> -	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv6",
> -			 "%d", &val) < 0)
> -		val = 0;
> -	if (val)
> +	if (xenbus_read_unsigned(dev->otherend, "feature-gso-tcpv6", 0))
>  		vif->gso_mask |= GSO_BIT(TCPV6);
> 
> -	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-
> offload",
> -			 "%d", &val) < 0)
> -		val = 0;
> -	vif->ip_csum = !val;
> +	vif->ip_csum = !xenbus_read_unsigned(dev->otherend,
> +					     "feature-no-csum-offload", 0);
> 
> -	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-
> offload",
> -			 "%d", &val) < 0)
> -		val = 0;
> -	vif->ipv6_csum = !!val;
> +	vif->ipv6_csum = !!xenbus_read_unsigned(dev->otherend,
> +						"feature-ipv6-csum-offload",
> 0);
> 
>  	return 0;
>  }
> --
> 2.6.6

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Re: [PATCH 00/12] xen: add common function for reading optional value

[David Vrabel]

On 31/10/16 16:48, Juergen Gross wrote:
> There are multiple instances of code reading an optional unsigned
> parameter from Xenstore via xenbus_scanf(). Instead of repeating the
> same code over and over add a service function doing the job and
> replace the call of xenbus_scanf() with the call of the new function
> where appropriate.

Acked-by: David Vrabel <david.vrabel@citrix.com>

Please queue for the next release.

David

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Re: [PATCH 00/12] xen: add common function for reading optional value

[Jarkko Sakkinen]

On Mon, Nov 07, 2016 at 11:08:09AM +0000, David Vrabel wrote:
> On 31/10/16 16:48, Juergen Gross wrote:
> > There are multiple instances of code reading an optional unsigned
> > parameter from Xenstore via xenbus_scanf(). Instead of repeating the
> > same code over and over add a service function doing the job and
> > replace the call of xenbus_scanf() with the call of the new function
> > where appropriate.
> 
> Acked-by: David Vrabel <david.vrabel@citrix.com>
> 
> Please queue for the next release.

If you want this change to tpmdd, please resend it to tpmdd mailing
list and CC it to linux-security-module. Thanks.

> David

/Jarkko

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Re: [PATCH 05/12] xen: make use of xenbus_read_unsigned() in xen-kbdfront

[Dmitry Torokhov]

On Mon, Oct 31, 2016 at 05:48:23PM +0100, Juergen Gross wrote:
> Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
> This requires to change the type of the reads from int to unsigned,
> but these cases have been wrong before: negative values are not allowed
> for the modified cases.
> 
> Cc: dmitry.torokhov@gmail.com
> Cc: linux-input@vger.kernel.org
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

> ---
>  drivers/input/misc/xen-kbdfront.c | 13 +++++--------
>  1 file changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
> index 227fbd2..3900875 100644
> --- a/drivers/input/misc/xen-kbdfront.c
> +++ b/drivers/input/misc/xen-kbdfront.c
> @@ -108,7 +108,8 @@ static irqreturn_t input_handler(int rq, void *dev_id)
>  static int xenkbd_probe(struct xenbus_device *dev,
>  				  const struct xenbus_device_id *id)
>  {
> -	int ret, i, abs;
> +	int ret, i;
> +	unsigned int abs;
>  	struct xenkbd_info *info;
>  	struct input_dev *kbd, *ptr;
>  
> @@ -127,8 +128,7 @@ static int xenkbd_probe(struct xenbus_device *dev,
>  	if (!info->page)
>  		goto error_nomem;
>  
> -	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-abs-pointer", "%d", &abs) < 0)
> -		abs = 0;
> +	abs = xenbus_read_unsigned(dev->otherend, "feature-abs-pointer", 0);
>  	if (abs) {
>  		ret = xenbus_write(XBT_NIL, dev->nodename,
>  				   "request-abs-pointer", "1");
> @@ -322,11 +322,8 @@ static void xenkbd_backend_changed(struct xenbus_device *dev,
>  
>  	case XenbusStateInitWait:
>  InitWait:
> -		ret = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
> -				   "feature-abs-pointer", "%d", &val);
> -		if (ret < 0)
> -			val = 0;
> -		if (val) {
> +		if (xenbus_read_unsigned(info->xbdev->otherend,
> +					 "feature-abs-pointer", 0)) {
>  			ret = xenbus_write(XBT_NIL, info->xbdev->nodename,
>  					   "request-abs-pointer", "1");
>  			if (ret)
> -- 
> 2.6.6
> 

-- 
Dmitry

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