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[Qemu-devel] [PATCH 1/5] block: Add top level BSG support
From: |
Nicholas A. Bellinger |
Subject: |
[Qemu-devel] [PATCH 1/5] block: Add top level BSG support |
Date: |
Wed, 24 Nov 2010 00:40:04 -0800 |
From: Nicholas Bellinger <address@hidden>
This patch adds top level BSG support to QEMU-KVM block and adds the
BDS_* prefixed defines for SG_IO and BSG.
It adds the BDS_SCSI_GENERIC and BDS_BSG assignments in
block/raw-posix.c:hdev_open()
using S_ISCHR() and major(st.st_rdev) in order to determine when we are dealing
with
scsi-generic or scsi-bsg backstores.
Signed-off-by: Nicholas A. Bellinger <address@hidden>
---
block.c | 7 +++++-
block.h | 1 +
block/raw-posix.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++---
block_int.h | 6 +++++
4 files changed, 74 insertions(+), 5 deletions(-)
diff --git a/block.c b/block.c
index 6b505fb..8faf25d 100644
--- a/block.c
+++ b/block.c
@@ -1340,7 +1340,12 @@ int bdrv_is_read_only(BlockDriverState *bs)
int bdrv_is_sg(BlockDriverState *bs)
{
- return bs->sg;
+ return bs->sg == BDS_SCSI_GENERIC;
+}
+
+int bdrv_is_bsg(BlockDriverState *bs)
+{
+ return bs->sg == BDS_BSG;
}
int bdrv_enable_write_cache(BlockDriverState *bs)
diff --git a/block.h b/block.h
index 78ecfac..5869c8c 100644
--- a/block.h
+++ b/block.h
@@ -174,6 +174,7 @@ void bdrv_set_removable(BlockDriverState *bs, int
removable);
int bdrv_is_removable(BlockDriverState *bs);
int bdrv_is_read_only(BlockDriverState *bs);
int bdrv_is_sg(BlockDriverState *bs);
+int bdrv_is_bsg(BlockDriverState *bs);
int bdrv_enable_write_cache(BlockDriverState *bs);
int bdrv_is_inserted(BlockDriverState *bs);
int bdrv_media_changed(BlockDriverState *bs);
diff --git a/block/raw-posix.c b/block/raw-posix.c
index bf89717..2802c97 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -53,6 +53,7 @@
#include <sys/param.h>
#include <linux/cdrom.h>
#include <linux/fd.h>
+#include <linux/major.h>
#endif
#if defined (__FreeBSD__) || defined(__FreeBSD_kernel__)
#include <signal.h>
@@ -885,13 +886,69 @@ static int hdev_open(BlockDriverState *bs, const char
*filename, int flags)
s->type = FTYPE_FILE;
#if defined(__linux__)
{
- char resolved_path[ MAXPATHLEN ], *temp;
+ struct stat st, st2;
+ FILE *file;
+ char major[8], dev[64], path[128], *p, *buf;
+ int ch, i;
- temp = realpath(filename, resolved_path);
- if (temp && strstart(temp, "/dev/sg", NULL)) {
- bs->sg = 1;
+ if (stat(filename, &st) < 0) {
+ printf("stat() failed errno: %d\n", errno);
+ return -1;
+ }
+
+ if (major(st.st_rdev) == SCSI_GENERIC_MAJOR) {
+ bs->sg = BDS_SCSI_GENERIC;
+ goto out;
+ }
+
+ memset(major, 0, 8);
+ memset(dev, 0, 64);
+ memset(path, 0, 128);
+
+ buf = strdup(filename);
+ if (!buf)
+ goto out;
+ /*
+ * Locate the device name from the path, we are interested
+ * in the last strsep() token..
+ */
+ while ((p = strsep(&buf, "/")))
+ snprintf(dev, 64, "%s", p);
+ /*
+ * Check to sure the sysfs entry exists before calling open
+ */
+ snprintf(path, 128, "/sys/class/bsg/%s/dev", dev);
+ if (stat(path, &st2) < 0) {
+ free(buf);
+ goto out;
+ }
+
+ file = fopen(path, "r");
+ if (!file) {
+ printf("fopen() failed for BSG sysfs path: %s\n", path);
+ free(buf);
+ goto out;
+ }
+ ch = fgetc(file);
+ for (i = 0; i < 7; i++) {
+ if (ch == ':') {
+ major[i] = '\0';
+ break;
+ }
+ major[i] = ch;
+ ch = fgetc(file);
}
+ fclose(file);
+ /*
+ * If the major returned by /sys/class/bsg/$H:C:T:L/dev matches
+ * stat(), then we signal BDS_BSG usage.
+ */
+ if (major(st.st_rdev) == atoi(major))
+ bs->sg = BDS_BSG;
+
+ free(buf);
}
+out:
#endif
return raw_open_common(bs, filename, flags, 0);
diff --git a/block_int.h b/block_int.h
index 3c3adb5..8fdc816 100644
--- a/block_int.h
+++ b/block_int.h
@@ -40,6 +40,11 @@
#define BLOCK_OPT_CLUSTER_SIZE "cluster_size"
#define BLOCK_OPT_PREALLOC "preallocation"
+/* Used for BlockDriverState->sg */
+#define BDS_NONE 0
+#define BDS_SCSI_GENERIC 1
+#define BDS_BSG 2
+
typedef struct AIOPool {
void (*cancel)(BlockDriverAIOCB *acb);
int aiocb_size;
@@ -150,6 +155,7 @@ struct BlockDriverState {
int encrypted; /* if true, the media is encrypted */
int valid_key; /* if true, a valid encryption key has been set */
int sg; /* if true, the device is a /dev/sg* */
+ int fd; /* Used for BSG file descriptor */
/* event callback when inserting/removing */
void (*change_cb)(void *opaque);
void *change_opaque;
--
1.5.6.5
- [Qemu-devel] [PATCH 1/5] block: Add top level BSG support,
Nicholas A. Bellinger <=