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Subject[PATCH 1/3] xen-blkfront: remove type check from blkfront_setup_discard
Date
In its initial implementation a check for "type" was added, but only phy
and file are handled. This breaks advertised discard support for other
type values such as qdisk.

Fix and simplify this function: If the backend advertises discard
support it is supposed to implement it properly, so enable
feature_discard unconditionally. If the backend advertises the need for
a certain granularity and alignment then propagate both properties to
the blocklayer. The discard-secure property is a boolean, update the code
to reflect that.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
drivers/block/xen-blkfront.c | 40 ++++++++++++++--------------------------
1 file changed, 14 insertions(+), 26 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index efe1b47..25c11ad 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1635,36 +1635,24 @@ blkfront_closing(struct blkfront_info *info)
static void blkfront_setup_discard(struct blkfront_info *info)
{
int err;
- char *type;
unsigned int discard_granularity;
unsigned int discard_alignment;
unsigned int discard_secure;

- type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
- if (IS_ERR(type))
- return;
-
- info->feature_secdiscard = 0;
- if (strncmp(type, "phy", 3) == 0) {
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "discard-granularity", "%u", &discard_granularity,
- "discard-alignment", "%u", &discard_alignment,
- NULL);
- if (!err) {
- info->feature_discard = 1;
- info->discard_granularity = discard_granularity;
- info->discard_alignment = discard_alignment;
- }
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "discard-secure", "%d", &discard_secure,
- NULL);
- if (!err)
- info->feature_secdiscard = discard_secure;
-
- } else if (strncmp(type, "file", 4) == 0)
- info->feature_discard = 1;
-
- kfree(type);
+ info->feature_discard = 1;
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "discard-granularity", "%u", &discard_granularity,
+ "discard-alignment", "%u", &discard_alignment,
+ NULL);
+ if (!err) {
+ info->discard_granularity = discard_granularity;
+ info->discard_alignment = discard_alignment;
+ }
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "discard-secure", "%d", &discard_secure,
+ NULL);
+ if (!err)
+ info->feature_secdiscard = !!discard_secure;
}

static int blkfront_setup_indirect(struct blkfront_info *info)

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