From: Christian Schoenebeck <qemu_oss@crudebyte.com>
To: qemu-devel@nongnu.org
Cc: Greg Kurz <groug@kaod.org>, Philippe Mathieu-Daudé <philmd@redhat.com>
Subject: [PATCH 1/2] 9pfs: deduplicate iounit code
Date: Mon, 27 Sep 2021 17:45:00 +0200 [thread overview]
Message-ID: <129bb71d5119e61d335f1e3107e472e4beea223a.1632758315.git.qemu_oss@crudebyte.com> (raw)
In-Reply-To: <cover.1632758315.git.qemu_oss@crudebyte.com>
Remove redundant code that translates host fileystem's block
size into 9p client (guest side) block size.
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
---
hw/9pfs/9p.c | 42 ++++++++++++++++++++----------------------
1 file changed, 20 insertions(+), 22 deletions(-)
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 708b030474..c65584173a 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1262,18 +1262,26 @@ static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu, V9fsPath *path,
#define P9_STATS_ALL 0x00003fffULL /* Mask for All fields above */
-static int32_t stat_to_iounit(const V9fsPDU *pdu, const struct stat *stbuf)
+/**
+ * Convert host filesystem's block size into an appropriate block size for
+ * 9p client (guest OS side). The value returned suggests an "optimum" block
+ * size for 9p I/O, i.e. to maximize performance.
+ *
+ * @pdu: 9p client request
+ * @blksize: host filesystem's block size
+ */
+static int32_t blksize_to_iounit(const V9fsPDU *pdu, int32_t blksize)
{
int32_t iounit = 0;
V9fsState *s = pdu->s;
/*
- * iounit should be multiples of st_blksize (host filesystem block size)
+ * iounit should be multiples of blksize (host filesystem block size)
* as well as less than (client msize - P9_IOHDRSZ)
*/
- if (stbuf->st_blksize) {
- iounit = stbuf->st_blksize;
- iounit *= (s->msize - P9_IOHDRSZ) / stbuf->st_blksize;
+ if (blksize) {
+ iounit = blksize;
+ iounit *= (s->msize - P9_IOHDRSZ) / blksize;
}
if (!iounit) {
iounit = s->msize - P9_IOHDRSZ;
@@ -1281,6 +1289,11 @@ static int32_t stat_to_iounit(const V9fsPDU *pdu, const struct stat *stbuf)
return iounit;
}
+static int32_t stat_to_iounit(const V9fsPDU *pdu, const struct stat *stbuf)
+{
+ return blksize_to_iounit(pdu, stbuf->st_blksize);
+}
+
static int stat_to_v9stat_dotl(V9fsPDU *pdu, const struct stat *stbuf,
V9fsStatDotl *v9lstat)
{
@@ -1899,23 +1912,8 @@ out_nofid:
static int32_t coroutine_fn get_iounit(V9fsPDU *pdu, V9fsPath *path)
{
struct statfs stbuf;
- int32_t iounit = 0;
- V9fsState *s = pdu->s;
-
- /*
- * iounit should be multiples of f_bsize (host filesystem block size
- * and as well as less than (client msize - P9_IOHDRSZ))
- */
- if (!v9fs_co_statfs(pdu, path, &stbuf)) {
- if (stbuf.f_bsize) {
- iounit = stbuf.f_bsize;
- iounit *= (s->msize - P9_IOHDRSZ) / stbuf.f_bsize;
- }
- }
- if (!iounit) {
- iounit = s->msize - P9_IOHDRSZ;
- }
- return iounit;
+ int err = v9fs_co_statfs(pdu, path, &stbuf);
+ return blksize_to_iounit(pdu, (err >= 0) ? stbuf.f_bsize : 0);
}
static void coroutine_fn v9fs_open(void *opaque)
--
2.20.1
next prev parent reply other threads:[~2021-09-27 16:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-27 15:44 [PATCH 0/2] 9pfs: iounit cleanup Christian Schoenebeck
2021-09-27 15:45 ` Christian Schoenebeck [this message]
2021-09-27 16:27 ` [PATCH 1/2] 9pfs: deduplicate iounit code Greg Kurz
2021-09-27 16:50 ` Christian Schoenebeck
2021-09-27 17:30 ` Greg Kurz
2021-09-27 15:50 ` [PATCH 2/2] 9pfs: simplify blksize_to_iounit() Christian Schoenebeck
2021-09-27 16:28 ` Greg Kurz
2021-09-27 17:53 ` Philippe Mathieu-Daudé
2021-09-28 11:53 ` [PATCH 0/2] 9pfs: iounit cleanup Christian Schoenebeck
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