ssh: Run restart_coroutine in current AioContext

restart_coroutine() is attached as an FD handler just to wake the
current coroutine after yielding.  It makes most sense to attach it to
the current (request) AioContext instead of the BDS main context.  This
way, the coroutine can be entered directly from the BH instead of having
yet another indirection through AioContext.co_schedule_bh.

Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20251110154854.151484-15-hreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/ssh.c

@@ -1010,19 +1010,18 @@ static int ssh_has_zero_init(BlockDriverState *bs)
 }
 
 typedef struct BDRVSSHRestart {
-    BlockDriverState *bs;
+    BDRVSSHState *s;
     Coroutine *co;
 } BDRVSSHRestart;
 
 static void restart_coroutine(void *opaque)
 {
     BDRVSSHRestart *restart = opaque;
-    BlockDriverState *bs = restart->bs;
-    BDRVSSHState *s = bs->opaque;
-    AioContext *ctx = bdrv_get_aio_context(bs);
+    BDRVSSHState *s = restart->s;
 
     trace_ssh_restart_coroutine(restart->co);
-    aio_set_fd_handler(ctx, s->sock, NULL, NULL, NULL, NULL, NULL);
+    aio_set_fd_handler(qemu_get_current_aio_context(), s->sock,
+                       NULL, NULL, NULL, NULL, NULL);
 
     aio_co_wake(restart->co);
 }
@@ -1031,12 +1030,13 @@ static void restart_coroutine(void *opaque)
  * handlers are set up so that we'll be rescheduled when there is an
  * interesting event on the socket.
  */
-static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
+static coroutine_fn void co_yield(BDRVSSHState *s)
 {
     int r;
     IOHandler *rd_handler = NULL, *wr_handler = NULL;
+    AioContext *ctx = qemu_get_current_aio_context();
     BDRVSSHRestart restart = {
-        .bs = bs,
+        .s = s,
         .co = qemu_coroutine_self()
     };
 
@@ -1051,7 +1051,7 @@ static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
 
     trace_ssh_co_yield(s->sock, rd_handler, wr_handler);
 
-    aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
+    aio_set_fd_handler(ctx, s->sock,
                        rd_handler, wr_handler, NULL, NULL, &restart);
     qemu_coroutine_yield();
     trace_ssh_co_yield_back(s->sock);
@@ -1093,7 +1093,7 @@ static coroutine_fn int ssh_read(BDRVSSHState *s, BlockDriverState *bs,
         trace_ssh_read_return(r, sftp_get_error(s->sftp));
 
         if (r == SSH_AGAIN) {
-            co_yield(s, bs);
+            co_yield(s);
             goto again;
         }
         if (r == SSH_EOF || (r == 0 && sftp_get_error(s->sftp) == SSH_FX_EOF)) {
@@ -1168,7 +1168,7 @@ static coroutine_fn int ssh_write(BDRVSSHState *s, BlockDriverState *bs,
         trace_ssh_write_return(r, sftp_get_error(s->sftp));
 
         if (r == SSH_AGAIN) {
-            co_yield(s, bs);
+            co_yield(s);
             goto again;
         }
         if (r < 0) {
@@ -1233,7 +1233,7 @@ static coroutine_fn int ssh_flush(BDRVSSHState *s, BlockDriverState *bs)
  again:
     r = sftp_fsync(s->sftp_handle);
     if (r == SSH_AGAIN) {
-        co_yield(s, bs);
+        co_yield(s);
         goto again;
     }
     if (r < 0) {