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[Qemu-devel] [PATCH 1/3] Add specialized block driver scsi generic API
From: |
Avi Kivity |
Subject: |
[Qemu-devel] [PATCH 1/3] Add specialized block driver scsi generic API |
Date: |
Thu, 12 Mar 2009 14:57:09 +0200 |
When a scsi device is backed by a scsi generic device instead of an
ordinary host block device, the block API is abused in a couple of annoying
ways:
- nb_sectors is negative, and specifies a byte count instead of a sector count
- offset is ignored, since scsi-generic is essentially a packet protocol
This overloading makes hacking the block layer difficult. Remove it by
introducing a new explicit API for scsi-generic devices. The new API
is still backed by the old implementation, but at least the users are
insulated.
Signed-off-by: Avi Kivity <address@hidden>
---
block.c | 22 ++++++++++++++++++++++
block.h | 8 ++++++++
hw/scsi-generic.c | 39 ++++++++++++++++++++++-----------------
3 files changed, 52 insertions(+), 17 deletions(-)
diff --git a/block.c b/block.c
index 1ef4ae5..39b27b2 100644
--- a/block.c
+++ b/block.c
@@ -1675,3 +1675,25 @@ int bdrv_ioctl(BlockDriverState *bs, unsigned long int
req, void *buf)
return drv->bdrv_ioctl(bs, req, buf);
return -ENOTSUP;
}
+
+int bdrv_sg_send_command(BlockDriverState *bs, void *buf, int count)
+{
+ return bdrv_pwrite(bs, -1, buf, count);
+}
+
+int bdrv_sg_recv_response(BlockDriverState *bs, void *buf, int count)
+{
+ return bdrv_pread(bs, -1, buf, count);
+}
+
+BlockDriverAIOCB *bdrv_sg_aio_read(BlockDriverState *bs, void *buf, int count,
+ BlockDriverCompletionFunc *cb, void *opaque)
+{
+ return bdrv_aio_read(bs, 0, buf, -(int64_t)count, cb, opaque);
+}
+
+BlockDriverAIOCB *bdrv_sg_aio_write(BlockDriverState *bs, void *buf, int count,
+ BlockDriverCompletionFunc *cb, void
*opaque)
+{
+ return bdrv_aio_write(bs, 0, buf, -(int64_t)count, cb, opaque);
+}
diff --git a/block.h b/block.h
index f6b14ee..b0c63ac 100644
--- a/block.h
+++ b/block.h
@@ -101,6 +101,14 @@ BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs,
int64_t sector_num,
BlockDriverCompletionFunc *cb, void *opaque);
void bdrv_aio_cancel(BlockDriverAIOCB *acb);
+/* sg packet commands */
+int bdrv_sg_send_command(BlockDriverState *bs, void *buf, int count);
+int bdrv_sg_recv_response(BlockDriverState *bs, void *buf, int count);
+BlockDriverAIOCB *bdrv_sg_aio_read(BlockDriverState *bs, void *buf, int count,
+ BlockDriverCompletionFunc *cb, void
*opaque);
+BlockDriverAIOCB *bdrv_sg_aio_write(BlockDriverState *bs, void *buf, int count,
+ BlockDriverCompletionFunc *cb, void
*opaque);
+
/* Ensure contents are flushed to disk. */
void bdrv_flush(BlockDriverState *bs);
void bdrv_flush_all(void);
diff --git a/hw/scsi-generic.c b/hw/scsi-generic.c
index 5bf160a..53e8951 100644
--- a/hw/scsi-generic.c
+++ b/hw/scsi-generic.c
@@ -201,6 +201,7 @@ static int execute_command(BlockDriverState *bdrv,
SCSIRequest *r, int direction,
BlockDriverCompletionFunc *complete)
{
+ int ret;
r->io_header.interface_id = 'S';
r->io_header.dxfer_direction = direction;
@@ -214,25 +215,27 @@ static int execute_command(BlockDriverState *bdrv,
r->io_header.usr_ptr = r;
r->io_header.flags |= SG_FLAG_DIRECT_IO;
- if (bdrv_pwrite(bdrv, -1, &r->io_header, sizeof(r->io_header)) == -1) {
+ ret = bdrv_sg_send_command(bdrv, &r->io_header, sizeof(r->io_header));
+ if (ret < 0) {
BADF("execute_command: write failed ! (%d)\n", errno);
return -1;
}
if (complete == NULL) {
int ret;
r->aiocb = NULL;
- while ((ret = bdrv_pread(bdrv, -1, &r->io_header,
- sizeof(r->io_header))) == -1 &&
- errno == EINTR);
- if (ret == -1) {
+ while ((ret = bdrv_sg_recv_response(bdrv, &r->io_header,
+ sizeof(r->io_header))) < 0 &&
+ ret == -EINTR)
+ ;
+ if (ret < 0) {
BADF("execute_command: read failed !\n");
return -1;
}
return 0;
}
- r->aiocb = bdrv_aio_read(bdrv, 0, (uint8_t*)&r->io_header,
- -(int64_t)sizeof(r->io_header), complete, r);
+ r->aiocb = bdrv_sg_aio_read(bdrv, (uint8_t*)&r->io_header,
+ sizeof(r->io_header), complete, r);
if (r->aiocb == NULL) {
BADF("execute_command: read failed !\n");
return -1;
@@ -634,14 +637,15 @@ static int get_blocksize(BlockDriverState *bdrv)
io_header.sbp = sensebuf;
io_header.timeout = 6000; /* XXX */
- ret = bdrv_pwrite(bdrv, -1, &io_header, sizeof(io_header));
- if (ret == -1)
+ ret = bdrv_sg_send_command(bdrv, &io_header, sizeof(io_header));
+ if (ret < 0)
return -1;
- while ((ret = bdrv_pread(bdrv, -1, &io_header, sizeof(io_header))) == -1 &&
- errno == EINTR);
+ while ((ret = bdrv_sg_recv_response(bdrv, &io_header, sizeof(io_header)))
< 0 &&
+ ret == -EINTR)
+ ;
- if (ret == -1)
+ if (ret < 0)
return -1;
return (buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7];
@@ -671,14 +675,15 @@ static int get_stream_blocksize(BlockDriverState *bdrv)
io_header.sbp = sensebuf;
io_header.timeout = 6000; /* XXX */
- ret = bdrv_pwrite(bdrv, -1, &io_header, sizeof(io_header));
- if (ret == -1)
+ ret = bdrv_sg_send_command(bdrv, &io_header, sizeof(io_header));
+ if (ret < 0)
return -1;
- while ((ret = bdrv_pread(bdrv, -1, &io_header, sizeof(io_header))) == -1 &&
- errno == EINTR);
+ while ((ret = bdrv_sg_recv_response(bdrv, &io_header, sizeof(io_header)))
< 0 &&
+ ret == -EINTR)
+ ;
- if (ret == -1)
+ if (ret < 0)
return -1;
return (buf[9] << 16) | (buf[10] << 8) | buf[11];
--
1.6.0.6
- [Qemu-devel] [PATCH 0/3] Remove ->bdrv_pread() internal block layer API (v2), Avi Kivity, 2009/03/12
- [Qemu-devel] [PATCH 1/3] Add specialized block driver scsi generic API,
Avi Kivity <=
- Re: [Qemu-devel] [PATCH 1/3] Add specialized block driver scsi generic API, Christoph Hellwig, 2009/03/14
- Re: [Qemu-devel] [PATCH 1/3] Add specialized block driver scsi generic API, Avi Kivity, 2009/03/15
- Re: [Qemu-devel] [PATCH 1/3] Add specialized block driver scsi generic API, Christoph Hellwig, 2009/03/15
- Re: [Qemu-devel] [PATCH 1/3] Add specialized block driver scsi generic API, Avi Kivity, 2009/03/15
- Re: [Qemu-devel] [PATCH 1/3] Add specialized block driver scsi generic API, Christoph Hellwig, 2009/03/15
- Re: [Qemu-devel] [PATCH 1/3] Add specialized block driver scsi generic API, Jamie Lokier, 2009/03/16
[Qemu-devel] [PATCH 3/3] Drop internal bdrv_pread()/bdrv_pwrite() APIs, Avi Kivity, 2009/03/12
[Qemu-devel] [PATCH 2/3] Add internal scsi generic block API, Avi Kivity, 2009/03/12
[Qemu-devel] Re: [PATCH 0/3] Remove ->bdrv_pread() internal block layer API (v2), Anthony Liguori, 2009/03/12