Staging: hv: storvsc: Cleanup storvsc_queuecommand()

Cleanup storvsc_queuecommand(). As part of this cleanup, rename the function to
check if the scsi command can be sent to the host, consolidate error recovery
and get rid of some dead code.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index 7561d298f6d348ba78ee637c9dc12b4e8c77ec09..71e50c333b821c702a952ef4b1e75b233cc9dc60 100644 (file)
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -1239,13 +1239,16 @@ static void storvsc_command_completion(struct hv_storvsc_request *request)
        mempool_free(cmd_request, memp->request_mempool);
 }
 
-static bool storvsc_check_scsi_cmd(struct scsi_cmnd *scmnd)
+static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
 {
        bool allowed = true;
        u8 scsi_op = scmnd->cmnd[0];
 
        switch (scsi_op) {
-       /* smartd sends this command, which will offline the device */
+       /*
+        * smartd sends this command and the host does not handle
+        * this. So, don't send it.
+        */
        case SET_WINDOW:
                scmnd->result = ILLEGAL_REQUEST << 16;
                allowed = false;
@@ -1270,32 +1273,26 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
        struct vmscsi_request *vm_srb;
        struct stor_mem_pools *memp = scmnd->device->hostdata;
 
-       if (storvsc_check_scsi_cmd(scmnd) == false) {
+       if (!storvsc_scsi_cmd_ok(scmnd)) {
                scmnd->scsi_done(scmnd);
                return 0;
        }
 
-       /* If retrying, no need to prep the cmd */
-       if (scmnd->host_scribble) {
-
-               cmd_request =
-                       (struct storvsc_cmd_request *)scmnd->host_scribble;
-
-               goto retry_request;
-       }
-
        request_size = sizeof(struct storvsc_cmd_request);
 
        cmd_request = mempool_alloc(memp->request_mempool,
                                       GFP_ATOMIC);
+
+       /*
+        * We might be invoked in an interrupt context; hence
+        * mempool_alloc() can fail.
+        */
        if (!cmd_request)
                return SCSI_MLQUEUE_DEVICE_BUSY;
 
        memset(cmd_request, 0, sizeof(struct storvsc_cmd_request));
 
        /* Setup the cmd request */
-       cmd_request->bounce_sgl_count = 0;
-       cmd_request->bounce_sgl = NULL;
        cmd_request->cmd = scmnd;
 
        scmnd->host_scribble = (unsigned char *)cmd_request;
@@ -1344,11 +1341,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
                                                     scsi_bufflen(scmnd),
                                                     vm_srb->data_in);
                        if (!cmd_request->bounce_sgl) {
-                               scmnd->host_scribble = NULL;
-                               mempool_free(cmd_request,
-                                               memp->request_mempool);
-
-                               return SCSI_MLQUEUE_HOST_BUSY;
+                               ret = SCSI_MLQUEUE_HOST_BUSY;
+                               goto queue_error;
                        }
 
                        cmd_request->bounce_sgl_count =
@@ -1377,24 +1371,26 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
                        virt_to_phys(scsi_sglist(scmnd)) >> PAGE_SHIFT;
        }
 
-retry_request:
        /* Invokes the vsc to start an IO */
        ret = storvsc_do_io(dev, &cmd_request->request);
 
        if (ret == -EAGAIN) {
                /* no more space */
 
-               if (cmd_request->bounce_sgl_count)
+               if (cmd_request->bounce_sgl_count) {
                        destroy_bounce_buffer(cmd_request->bounce_sgl,
                                        cmd_request->bounce_sgl_count);
 
-               mempool_free(cmd_request, memp->request_mempool);
-
-               scmnd->host_scribble = NULL;
-
-               ret = SCSI_MLQUEUE_DEVICE_BUSY;
+                       ret = SCSI_MLQUEUE_DEVICE_BUSY;
+                       goto queue_error;
+               }
        }
 
+       return 0;
+
+queue_error:
+       mempool_free(cmd_request, memp->request_mempool);
+       scmnd->host_scribble = NULL;
        return ret;
 }