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authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-03-28 17:28:41 +0000
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-03-28 17:28:41 +0000
commit221f715d90ec5fec569a19119887445c037bca86 (patch)
tree01d6f162df77773cf09c6193c6dc84219f297370 /posix-aio-compat.c
parent64a7fde8e85fbadb0dadee6ed1c293cd86f5fb29 (diff)
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new scsi-generic abstraction, use SG_IO (Christoph Hellwig)
Okay, I started looking into how to handle scsi-generic I/O in the new world order. I think the best is to use the SG_IO ioctl instead of the read/write interface as that allows us to support scsi passthrough on disk/cdrom devices, too. See Hannes patch on the kvm list from August for an example. Now that we always do ioctls we don't need another abstraction than bdrv_ioctl for the synchronous requests for now, and for asynchronous requests I've added a aio_ioctl abstraction keeping it simple. Long-term we might want to move the ops to a higher-level abstraction and let the low-level code fill out the request header, but I'm lazy enough to leave that to the people trying to support scsi-passthrough on a non-Linux OS. Tested lightly by issuing various sg_ commands from sg3-utils in a guest to a host CDROM device. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6895 c046a42c-6fe2-441c-8c8c-71466251a162
Diffstat (limited to 'posix-aio-compat.c')
-rw-r--r--posix-aio-compat.c100
1 files changed, 66 insertions, 34 deletions
diff --git a/posix-aio-compat.c b/posix-aio-compat.c
index 6b547f4..65c80ec 100644
--- a/posix-aio-compat.c
+++ b/posix-aio-compat.c
@@ -11,6 +11,7 @@
*
*/
+#include <sys/ioctl.h>
#include <pthread.h>
#include <unistd.h>
#include <errno.h>
@@ -75,6 +76,47 @@ static void thread_create(pthread_t *thread, pthread_attr_t *attr,
if (ret) die2(ret, "pthread_create");
}
+static size_t handle_aiocb_readwrite(struct qemu_paiocb *aiocb)
+{
+ size_t offset = 0;
+ ssize_t len;
+
+ while (offset < aiocb->aio_nbytes) {
+ if (aiocb->aio_type == QEMU_PAIO_WRITE)
+ len = pwrite(aiocb->aio_fildes,
+ (const char *)aiocb->aio_buf + offset,
+ aiocb->aio_nbytes - offset,
+ aiocb->aio_offset + offset);
+ else
+ len = pread(aiocb->aio_fildes,
+ (char *)aiocb->aio_buf + offset,
+ aiocb->aio_nbytes - offset,
+ aiocb->aio_offset + offset);
+
+ if (len == -1 && errno == EINTR)
+ continue;
+ else if (len == -1) {
+ offset = -errno;
+ break;
+ } else if (len == 0)
+ break;
+
+ offset += len;
+ }
+
+ return offset;
+}
+
+static size_t handle_aiocb_ioctl(struct qemu_paiocb *aiocb)
+{
+ int ret;
+
+ ret = ioctl(aiocb->aio_fildes, aiocb->aio_ioctl_cmd, aiocb->aio_buf);
+ if (ret == -1)
+ return -errno;
+ return ret;
+}
+
static void *aio_thread(void *unused)
{
pid_t pid;
@@ -88,8 +130,7 @@ static void *aio_thread(void *unused)
while (1) {
struct qemu_paiocb *aiocb;
- size_t offset;
- int ret = 0;
+ size_t ret = 0;
qemu_timeval tv;
struct timespec ts;
@@ -109,40 +150,26 @@ static void *aio_thread(void *unused)
aiocb = TAILQ_FIRST(&request_list);
TAILQ_REMOVE(&request_list, aiocb, node);
-
- offset = 0;
aiocb->active = 1;
-
idle_threads--;
mutex_unlock(&lock);
- while (offset < aiocb->aio_nbytes) {
- ssize_t len;
-
- if (aiocb->is_write)
- len = pwrite(aiocb->aio_fildes,
- (const char *)aiocb->aio_buf + offset,
- aiocb->aio_nbytes - offset,
- aiocb->aio_offset + offset);
- else
- len = pread(aiocb->aio_fildes,
- (char *)aiocb->aio_buf + offset,
- aiocb->aio_nbytes - offset,
- aiocb->aio_offset + offset);
-
- if (len == -1 && errno == EINTR)
- continue;
- else if (len == -1) {
- offset = -errno;
- break;
- } else if (len == 0)
- break;
-
- offset += len;
- }
+ switch (aiocb->aio_type) {
+ case QEMU_PAIO_READ:
+ case QEMU_PAIO_WRITE:
+ ret = handle_aiocb_readwrite(aiocb);
+ break;
+ case QEMU_PAIO_IOCTL:
+ ret = handle_aiocb_ioctl(aiocb);
+ break;
+ default:
+ fprintf(stderr, "invalid aio request (0x%x)\n", aiocb->aio_type);
+ ret = -EINVAL;
+ break;
+ }
mutex_lock(&lock);
- aiocb->ret = offset;
+ aiocb->ret = ret;
idle_threads++;
mutex_unlock(&lock);
@@ -178,9 +205,9 @@ int qemu_paio_init(struct qemu_paioinit *aioinit)
return 0;
}
-static int qemu_paio_submit(struct qemu_paiocb *aiocb, int is_write)
+static int qemu_paio_submit(struct qemu_paiocb *aiocb, int type)
{
- aiocb->is_write = is_write;
+ aiocb->aio_type = type;
aiocb->ret = -EINPROGRESS;
aiocb->active = 0;
mutex_lock(&lock);
@@ -195,12 +222,17 @@ static int qemu_paio_submit(struct qemu_paiocb *aiocb, int is_write)
int qemu_paio_read(struct qemu_paiocb *aiocb)
{
- return qemu_paio_submit(aiocb, 0);
+ return qemu_paio_submit(aiocb, QEMU_PAIO_READ);
}
int qemu_paio_write(struct qemu_paiocb *aiocb)
{
- return qemu_paio_submit(aiocb, 1);
+ return qemu_paio_submit(aiocb, QEMU_PAIO_WRITE);
+}
+
+int qemu_paio_ioctl(struct qemu_paiocb *aiocb)
+{
+ return qemu_paio_submit(aiocb, QEMU_PAIO_IOCTL);
}
ssize_t qemu_paio_return(struct qemu_paiocb *aiocb)