hw/scsi: centralize SG_IO calls into single function

For the VPD Block Limits emulation with SCSI passthrough,
we'll issue an Inquiry request with EVPD set to retrieve
the available VPD pages of the device. This would be done in
a way similar of what scsi_generic_read_device_identification
does: create a SCSI command and a reply buffer, fill in the
sg_io_hdr_t structure, call blk_ioctl, check if an error
occurred, process the response.

This same process is done in other 2 functions, get_device_type
and get_stream_blocksize. They differ in the command/reply
buffer and post-processing, everything else is almost a
copy/paste.

Instead of adding a forth copy/pasted-ish code when adding
the passthrough VPD BL emulation, this patch extirpates
this repetition of those 3 functions and put it into
a new one called scsi_SG_IO_FROM_DEV. Any future code that
wants to execute an SG_DXFER_FROM_DEV to the device can
use it, avoiding filling sg_io_hdr_t again and et cetera.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20180627172432.11120-3-danielhb413@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index 664d634c982df79bc8e7b36b556da72209153a2d..b0b39f1e920cf520c9f9190b1a3c4de0666c4363 100644 (file)
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -2578,8 +2578,6 @@ static int get_device_type(SCSIDiskState *s)
 {
     uint8_t cmd[16];
     uint8_t buf[36];
-    uint8_t sensebuf[8];
-    sg_io_hdr_t io_header;
     int ret;
 
     memset(cmd, 0, sizeof(cmd));
@@ -2587,19 +2585,9 @@ static int get_device_type(SCSIDiskState *s)
     cmd[0] = INQUIRY;
     cmd[4] = sizeof(buf);
 
-    memset(&io_header, 0, sizeof(io_header));
-    io_header.interface_id = 'S';
-    io_header.dxfer_direction = SG_DXFER_FROM_DEV;
-    io_header.dxfer_len = sizeof(buf);
-    io_header.dxferp = buf;
-    io_header.cmdp = cmd;
-    io_header.cmd_len = sizeof(cmd);
-    io_header.mx_sb_len = sizeof(sensebuf);
-    io_header.sbp = sensebuf;
-    io_header.timeout = 6000; /* XXX */
-
-    ret = blk_ioctl(s->qdev.conf.blk, SG_IO, &io_header);
-    if (ret < 0 || io_header.driver_status || io_header.host_status) {
+    ret = scsi_SG_IO_FROM_DEV(s->qdev.conf.blk, cmd, sizeof(cmd),
+                              buf, sizeof(buf));
+    if (ret < 0) {
         return -1;
     }
     s->qdev.type = buf[0];

diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index a04a704bbf40bfc525dce5a7763092ca6ba69839..61abc2763a1e548916bc54e877da69ecfbbda097 100644 (file)
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -409,35 +409,48 @@ static int read_naa_id(const uint8_t *p, uint64_t *p_wwn)
     return -EINVAL;
 }
 
-void scsi_generic_read_device_identification(SCSIDevice *s)
+int scsi_SG_IO_FROM_DEV(BlockBackend *blk, uint8_t *cmd, uint8_t cmd_size,
+                        uint8_t *buf, uint8_t buf_size)
 {
-    uint8_t cmd[6];
-    uint8_t buf[250];
-    uint8_t sensebuf[8];
     sg_io_hdr_t io_header;
+    uint8_t sensebuf[8];
     int ret;
-    int i, len;
-
-    memset(cmd, 0, sizeof(cmd));
-    memset(buf, 0, sizeof(buf));
-    cmd[0] = INQUIRY;
-    cmd[1] = 1;
-    cmd[2] = 0x83;
-    cmd[4] = sizeof(buf);
 
     memset(&io_header, 0, sizeof(io_header));
     io_header.interface_id = 'S';
     io_header.dxfer_direction = SG_DXFER_FROM_DEV;
-    io_header.dxfer_len = sizeof(buf);
+    io_header.dxfer_len = buf_size;
     io_header.dxferp = buf;
     io_header.cmdp = cmd;
-    io_header.cmd_len = sizeof(cmd);
+    io_header.cmd_len = cmd_size;
     io_header.mx_sb_len = sizeof(sensebuf);
     io_header.sbp = sensebuf;
     io_header.timeout = 6000; /* XXX */
 
-    ret = blk_ioctl(s->conf.blk, SG_IO, &io_header);
+    ret = blk_ioctl(blk, SG_IO, &io_header);
     if (ret < 0 || io_header.driver_status || io_header.host_status) {
+        return -1;
+    }
+    return 0;
+}
+
+void scsi_generic_read_device_identification(SCSIDevice *s)
+{
+    uint8_t cmd[6];
+    uint8_t buf[250];
+    int ret;
+    int i, len;
+
+    memset(cmd, 0, sizeof(cmd));
+    memset(buf, 0, sizeof(buf));
+    cmd[0] = INQUIRY;
+    cmd[1] = 1;
+    cmd[2] = 0x83;
+    cmd[4] = sizeof(buf);
+
+    ret = scsi_SG_IO_FROM_DEV(s->conf.blk, cmd, sizeof(cmd),
+                              buf, sizeof(buf));
+    if (ret < 0) {
         return;
     }
 
@@ -470,8 +483,6 @@ static int get_stream_blocksize(BlockBackend *blk)
 {
     uint8_t cmd[6];
     uint8_t buf[12];
-    uint8_t sensebuf[8];
-    sg_io_hdr_t io_header;
     int ret;
 
     memset(cmd, 0, sizeof(cmd));
@@ -479,21 +490,11 @@ static int get_stream_blocksize(BlockBackend *blk)
     cmd[0] = MODE_SENSE;
     cmd[4] = sizeof(buf);
 
-    memset(&io_header, 0, sizeof(io_header));
-    io_header.interface_id = 'S';
-    io_header.dxfer_direction = SG_DXFER_FROM_DEV;
-    io_header.dxfer_len = sizeof(buf);
-    io_header.dxferp = buf;
-    io_header.cmdp = cmd;
-    io_header.cmd_len = sizeof(cmd);
-    io_header.mx_sb_len = sizeof(sensebuf);
-    io_header.sbp = sensebuf;
-    io_header.timeout = 6000; /* XXX */
-
-    ret = blk_ioctl(blk, SG_IO, &io_header);
-    if (ret < 0 || io_header.driver_status || io_header.host_status) {
+    ret = scsi_SG_IO_FROM_DEV(blk, cmd, sizeof(cmd), buf, sizeof(buf));
+    if (ret < 0) {
         return -1;
     }
+
     return (buf[9] << 16) | (buf[10] << 8) | buf[11];
 }
 

diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h
index 138eb79a5fde1db280fef0021f8c65fb6e966074..75eced34d3999a20beac74f55fcc83fca65b7ba8 100644 (file)
--- a/include/hw/scsi/scsi.h
+++ b/include/hw/scsi/scsi.h
@@ -187,6 +187,8 @@ void scsi_device_unit_attention_reported(SCSIDevice *dev);
 void scsi_generic_read_device_identification(SCSIDevice *dev);
 int scsi_device_get_sense(SCSIDevice *dev, uint8_t *buf, int len, bool fixed);
 int scsi_disk_emulate_vpd_page(SCSIRequest *req, uint8_t *outbuf);
+int scsi_SG_IO_FROM_DEV(BlockBackend *blk, uint8_t *cmd, uint8_t cmd_size,
+                        uint8_t *buf, uint8_t buf_size);
 SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int target, int lun);
 
 /* scsi-generic.c. */