host ==> CBW ==> device
host <== CSW <== device
usb_sg_init() //初始化一個sg請求;
usb_sg_wait() //送出一個sg請求;
usb_sg_cancel() //取消一個sg請求;
裝置對于大多數讀操作的錯誤不需要使用sense buffer，
因為他們對于讀操作的錯誤通常會停止掉bulk_in pipe,
是以也就不需要再檢測sense buffer了，因為檢測sense buffer的目的無非就是
出錯了以後想知道出錯的原因。
usb總線上的資料是little-endian的。
static int usb_stor_control_thread(void * __us)
{
struct us_data *us = (struct us_data *)__us;
struct Scsi_Host *host = us_to_host(us);
for(;;) {
US_DEBUGP("*** thread sleeping.\n");
//處理完上一個指令之後，程序就會睡眠在us->cmnd_ready上。
//如果scsi層有指令發過來，scsi就會complete(&us->cmnd_ready)
//以此來喚醒 usb_stor_control_thread()
//還有一種情況可以喚醒usb_stor_control_thread()的情況就是
//usb_stor_disconnect(),該函數也會喚醒該程序
//void usb_stor_disconnect(struct usb_interface *intf)
//+-- release_everything(us);
// +-- usb_stor_release_resources(us);
// +-- complete(&us->cmnd_ready); -- 這裡也會喚醒程序
// +-- kthread_stop(us->ctl_thread);
// +-- usb_free_urb(us->current_urb);
if (wait_for_completion_interruptible(&us->cmnd_ready))
break;
US_DEBUGP("*** thread awakened.\n");
/* lock the device pointers */
mutex_lock(&(us->dev_mutex));
/* lock access to the state */
scsi_lock(host);
/* When we are called with no command pending, we're done */
//usb_stor_control_thread()在完成目前指令之後，會将us->srb置位null
//然後睡眠在us->cmnd_ready上，有scsi指令到來或者裝置disconnect的時候會将其
//喚醒，前者srb非空，後者srb為空。
//是以，如果us->srb為null，說明usb_stor_disconnect()被調用了,是以
//直接break，退出程序。
if (us->srb == NULL) {
scsi_unlock(host);
mutex_unlock(&us->dev_mutex);
US_DEBUGP("-- exiting\n");
break;
}
/* has the command timed out *already* ? */
//command_abort() 函數會将us->dflags置上US_FLIDX_TIMED_OUT
//這個标志位，是以檢測到US_FLIDX_TIMED_OUT标志之後直接SkipForAbort
//跳過對目前指令的處理
if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
us->srb->result = DID_ABORT << 16;
goto SkipForAbort;
}
scsi_unlock(host);
//#########################################################
//對command進行各種檢驗，對于不合理的command，過濾掉并回報給scsi
//如果command能夠通過各種檢驗，則調用us->transport()對其進行處理
/* reject the command if the direction indicator
* is UNKNOWN
*/
//對于傳輸方向未知的command，直接上報傳輸錯誤
if (us->srb->sc_data_direction == DMA_BIDIRECTIONAL) {
US_DEBUGP("UNKNOWN data direction\n");
us->srb->result = DID_ERROR << 16;
}
/* reject if target != 0 or if LUN is higher than
* the maximum known LUN
*/
//如果是非mult_target,device->id必須為0
//如果device->id不為0，上報scsi srb->result為bad target
else if (us->srb->device->id &&
!(us->fflags & US_FL_SCM_MULT_TARG)) {
US_DEBUGP("Bad target number (%d:%d)\n",
us->srb->device->id, us->srb->device->lun);
us->srb->result = DID_BAD_TARGET << 16;
}
//us->srb->device->lun不能超過us->max_lun，如果超過
//上報scsi srb->result為bad target
else if (us->srb->device->lun > us->max_lun) {
US_DEBUGP("Bad LUN (%d:%d)\n",
us->srb->device->id, us->srb->device->lun);
us->srb->result = DID_BAD_TARGET << 16;
}
/* Handle those devices which need us to fake
* their inquiry data */
//如果指令為INQUIRY,并且us->fflags置位了US_FL_FIX_INQUIRY标志
//則用data_ptr[]改寫srb->sense_buffer[],并上報scsi
//srb->result為 SAM_STAT_GOOD
else if ((us->srb->cmnd[0] == INQUIRY) &&
(us->fflags & US_FL_FIX_INQUIRY)) {
unsigned char data_ptr[36] = {
0x00, 0x80, 0x02, 0x02,
0x1F, 0x00, 0x00, 0x00};
US_DEBUGP("Faking INQUIRY command\n");
fill_inquiry_response(us, data_ptr, 36);
us->srb->result = SAM_STAT_GOOD;
}
/* we've got a command, let's do it! */
//如果以上驗證都通過，則調用proto_handler()對command進行處理
else {
US_DEBUG(usb_stor_show_command(us->srb));
//static int storage_probe(struct usb_interface *intf,
// const struct usb_device_id *id)
//+-- usb_stor_probe1(&us, intf, id, unusual_dev);
// +-- get_protocol(us);
// +-- us->proto_handler = usb_stor_invoke_transport;
//是以這裡usb_stor_invoke_transport()就是負責實際資料傳輸動作的函數
us->proto_handler(us->srb, us);
usb_mark_last_busy(us->pusb_dev);
}
/* lock access to the state */
scsi_lock(host);
/* indicate that the command is done */
//調用scsi_done()來通知scsi層，指令已經完成
if (us->srb->result != DID_ABORT << 16) {
US_DEBUGP("scsi cmd done, result=0x%x\n",
us->srb->result);
us->srb->scsi_done(us->srb);
} else {
SkipForAbort:
US_DEBUGP("scsi command aborted\n");
}
/* If an abort request was received we need to signal that
* the abort has finished. The proper test for this is
* the TIMED_OUT flag, not srb->result == DID_ABORT, because
* the timeout might have occurred after the command had
* already completed with a different result code. */
if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
//喚醒等待在us->notify上的command_abort()所在的線程
complete(&(us->notify));
/* Allow USB transfers to resume */
clear_bit(US_FLIDX_ABORTING, &us->dflags);
clear_bit(US_FLIDX_TIMED_OUT, &us->dflags);
}
/* finished working on this command */
//目前指令已經處理完成，是以将us->srb置為null
us->srb = NULL;
scsi_unlock(host);
/* unlock the device pointers */
mutex_unlock(&us->dev_mutex);
} /* for (;;) */
/* Wait until we are told to stop */
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop())
break;
schedule();
}
__set_current_state(TASK_RUNNING);
return 0;
}
// usb_stor_invoke_transport()調用us->transport()進行實際的資料傳輸，
// 然後檢驗傳輸的結果如何，并對srb->result進行指派，以此來告知scsi傳輸的結果如何
// srb是usb和scsi進行溝通的媒介，可以通過srb->result來通知scsi層傳輸成功與否
void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
{
int need_auto_sense;
int result;
/* send the command to the transport layer */
scsi_set_resid(srb, 0);
//進行實際的資料傳輸動作
result = us->transport(srb, us);
/* if the command gets aborted by the higher layers, we need to
* short-circuit all other processing
*/
if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
US_DEBUGP("-- command was aborted\n");
srb->result = DID_ABORT << 16;
goto Handle_Errors;
}
/* if there is a transport error, reset and don't auto-sense */
if (result == USB_STOR_TRANSPORT_ERROR) {
US_DEBUGP("-- transport indicates error, resetting\n");
srb->result = DID_ERROR << 16;
goto Handle_Errors;
}
/* if the transport provided its own sense data, don't auto-sense */
if (result == USB_STOR_TRANSPORT_NO_SENSE) {
srb->result = SAM_STAT_CHECK_CONDITION;
last_sector_hacks(us, srb);
return;
}
srb->result = SAM_STAT_GOOD;
/* Determine if we need to auto-sense
*
* I normally don't use a flag like this, but it's almost impossible
* to understand what's going on here if I don't.
*/
need_auto_sense = 0;
/*
* If we're running the CB transport, which is incapable
* of determining status on its own, we will auto-sense
* unless the operation involved a data-in transfer. Devices
* can signal most data-in errors by stalling the bulk-in pipe.
*/
if ((us->protocol == USB_PR_CB || us->protocol == USB_PR_DPCM_USB) &&
srb->sc_data_direction != DMA_FROM_DEVICE) {
US_DEBUGP("-- CB transport device requiring auto-sense\n");
need_auto_sense = 1;
}
/*
* If we have a failure, we're going to do a REQUEST_SENSE
* automatically. Note that we differentiate between a command
* "failure" and an "error" in the transport mechanism.
*/
if (result == USB_STOR_TRANSPORT_FAILED) {
US_DEBUGP("-- transport indicates command failure\n");
need_auto_sense = 1;
}
/*
* Determine if this device is SAT by seeing if the
* command executed successfully. Otherwise we'll have
* to wait for at least one CHECK_CONDITION to determine
* SANE_SENSE support
*/
if (unlikely((srb->cmnd[0] == ATA_16 || srb->cmnd[0] == ATA_12) &&
result == USB_STOR_TRANSPORT_GOOD &&
!(us->fflags & US_FL_SANE_SENSE) &&
!(us->fflags & US_FL_BAD_SENSE) &&
!(srb->cmnd[2] & 0x20))) {
US_DEBUGP("-- SAT supported, increasing auto-sense\n");
us->fflags |= US_FL_SANE_SENSE;
}
/*
* A short transfer on a command where we don't expect it
* is unusual, but it doesn't mean we need to auto-sense.
*/
if ((scsi_get_resid(srb) > 0) &&
!((srb->cmnd[0] == REQUEST_SENSE) ||
(srb->cmnd[0] == INQUIRY) ||
(srb->cmnd[0] == MODE_SENSE) ||
(srb->cmnd[0] == LOG_SENSE) ||
(srb->cmnd[0] == MODE_SENSE_10))) {
US_DEBUGP("-- unexpectedly short transfer\n");
}
/* Now, if we need to do the auto-sense, let's do it */
if (need_auto_sense) {
int temp_result;
struct scsi_eh_save ses;
int sense_size = US_SENSE_SIZE;
struct scsi_sense_hdr sshdr;
const u8 *scdd;
u8 fm_ili;
/* device supports and needs bigger sense buffer */
if (us->fflags & US_FL_SANE_SENSE)
sense_size = ~0;
Retry_Sense:
US_DEBUGP("Issuing auto-REQUEST_SENSE\n");
scsi_eh_prep_cmnd(srb, &ses, NULL, 0, sense_size);
/* FIXME: we must do the protocol translation here */
if (us->subclass == USB_SC_RBC || us->subclass == USB_SC_SCSI ||
us->subclass == USB_SC_CYP_ATACB)
srb->cmd_len = 6;
else
srb->cmd_len = 12;
/* issue the auto-sense command */
scsi_set_resid(srb, 0);
temp_result = us->transport(us->srb, us);
/* let's clean up right away */
scsi_eh_restore_cmnd(srb, &ses);
if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
US_DEBUGP("-- auto-sense aborted\n");
srb->result = DID_ABORT << 16;
/* If SANE_SENSE caused this problem, disable it */
if (sense_size != US_SENSE_SIZE) {
us->fflags &= ~US_FL_SANE_SENSE;
us->fflags |= US_FL_BAD_SENSE;
}
goto Handle_Errors;
}
/* Some devices claim to support larger sense but fail when
* trying to request it. When a transport failure happens
* using US_FS_SANE_SENSE, we always retry with a standard
* (small) sense request. This fixes some USB GSM modems
*/
if (temp_result == USB_STOR_TRANSPORT_FAILED &&
sense_size != US_SENSE_SIZE) {
US_DEBUGP("-- auto-sense failure, retry small sense\n");
sense_size = US_SENSE_SIZE;
us->fflags &= ~US_FL_SANE_SENSE;
us->fflags |= US_FL_BAD_SENSE;
goto Retry_Sense;
}
/* Other failures */
if (temp_result != USB_STOR_TRANSPORT_GOOD) {
US_DEBUGP("-- auto-sense failure\n");
/* we skip the reset if this happens to be a
* multi-target device, since failure of an
* auto-sense is perfectly valid
*/
srb->result = DID_ERROR << 16;
if (!(us->fflags & US_FL_SCM_MULT_TARG))
goto Handle_Errors;
return;
}
/* If the sense data returned is larger than 18-bytes then we
* assume this device supports requesting more in the future.
* The response code must be 70h through 73h inclusive.
*/
if (srb->sense_buffer[7] > (US_SENSE_SIZE - 8) &&
!(us->fflags & US_FL_SANE_SENSE) &&
!(us->fflags & US_FL_BAD_SENSE) &&
(srb->sense_buffer[0] & 0x7C) == 0x70) {
US_DEBUGP("-- SANE_SENSE support enabled\n");
us->fflags |= US_FL_SANE_SENSE;
/* Indicate to the user that we truncated their sense
* because we didn't know it supported larger sense.
*/
US_DEBUGP("-- Sense data truncated to %i from %i\n",
US_SENSE_SIZE,
srb->sense_buffer[7] + 8);
srb->sense_buffer[7] = (US_SENSE_SIZE - 8);
}
scsi_normalize_sense(srb->sense_buffer, SCSI_SENSE_BUFFERSIZE,
&sshdr);
US_DEBUGP("-- Result from auto-sense is %d\n", temp_result);
US_DEBUGP("-- code: 0x%x, key: 0x%x, ASC: 0x%x, ASCQ: 0x%x\n",
sshdr.response_code, sshdr.sense_key,
sshdr.asc, sshdr.ascq);
#ifdef CONFIG_USB_STORAGE_DEBUG
usb_stor_show_sense(sshdr.sense_key, sshdr.asc, sshdr.ascq);
#endif
/* set the result so the higher layers expect this data */
srb->result = SAM_STAT_CHECK_CONDITION;
scdd = scsi_sense_desc_find(srb->sense_buffer,
SCSI_SENSE_BUFFERSIZE, 4);
fm_ili = (scdd ? scdd[3] : srb->sense_buffer[2]) & 0xA0;
/* We often get empty sense data. This could indicate that
* everything worked or that there was an unspecified
* problem. We have to decide which.
*/
if (sshdr.sense_key == 0 && sshdr.asc == 0 && sshdr.ascq == 0 &&
fm_ili == 0) {
/* If things are really okay, then let's show that.
* Zero out the sense buffer so the higher layers
* won't realize we did an unsolicited auto-sense.
*/
if (result == USB_STOR_TRANSPORT_GOOD) {
srb->result = SAM_STAT_GOOD;
srb->sense_buffer[0] = 0x0;
/* If there was a problem, report an unspecified
* hardware error to prevent the higher layers from
* entering an infinite retry loop.
*/
} else {
srb->result = DID_ERROR << 16;
if ((sshdr.response_code & 0x72) == 0x72)
srb->sense_buffer[1] = HARDWARE_ERROR;
else
srb->sense_buffer[2] = HARDWARE_ERROR;
}
}
}
/*
* Some devices don't work or return incorrect data the first
* time they get a READ(10) command, or for the first READ(10)
* after a media change. If the INITIAL_READ10 flag is set,
* keep track of whether READ(10) commands succeed. If the
* previous one succeeded and this one failed, set the REDO_READ10
* flag to force a retry.
*/
if (unlikely((us->fflags & US_FL_INITIAL_READ10) &&
srb->cmnd[0] == READ_10)) {
if (srb->result == SAM_STAT_GOOD) {
set_bit(US_FLIDX_READ10_WORKED, &us->dflags);
} else if (test_bit(US_FLIDX_READ10_WORKED, &us->dflags)) {
clear_bit(US_FLIDX_READ10_WORKED, &us->dflags);
set_bit(US_FLIDX_REDO_READ10, &us->dflags);
}
/*
* Next, if the REDO_READ10 flag is set, return a result
* code that will cause the SCSI core to retry the READ(10)
* command immediately.
*/
if (test_bit(US_FLIDX_REDO_READ10, &us->dflags)) {
clear_bit(US_FLIDX_REDO_READ10, &us->dflags);
srb->result = DID_IMM_RETRY << 16;
srb->sense_buffer[0] = 0;
}
}
/* Did we transfer less than the minimum amount required? */
if ((srb->result == SAM_STAT_GOOD || srb->sense_buffer[2] == 0) &&
scsi_bufflen(srb) - scsi_get_resid(srb) < srb->underflow)
srb->result = DID_ERROR << 16;
last_sector_hacks(us, srb);
return;
/* Error and abort processing: try to resynchronize with the device
* by issuing a port reset. If that fails, try a class-specific
* device reset. */
Handle_Errors:
/* Set the RESETTING bit, and clear the ABORTING bit so that
* the reset may proceed. */
scsi_lock(us_to_host(us));
set_bit(US_FLIDX_RESETTING, &us->dflags);
clear_bit(US_FLIDX_ABORTING, &us->dflags);
scsi_unlock(us_to_host(us));
/* We must release the device lock because the pre_reset routine
* will want to acquire it. */
mutex_unlock(&us->dev_mutex);
result = usb_stor_port_reset(us);
mutex_lock(&us->dev_mutex);
if (result < 0) {
scsi_lock(us_to_host(us));
usb_stor_report_device_reset(us);
scsi_unlock(us_to_host(us));
us->transport_reset(us);
}
clear_bit(US_FLIDX_RESETTING, &us->dflags);
last_sector_hacks(us, srb);
}
//get_transport(struct us_data *us)
//+-- us->transport = usb_stor_Bulk_transport;
//usb_stor_invoke_transport()
//+-- temp_result = us->transport(us->srb, us);
// +== usb_stor_Bulk_transport(us->srb, us)
//是負責實際資料傳輸動作的函數,BULK傳輸主要分為三個階段：
// 1. 指令階段
// 2. 資料階段
// 3. 狀态階段
// 是以，usb_stor_Bulk_transport()的代碼流程也分為這樣三個階段 ：
int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
{
struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
struct bulk_cs_wrap *bcs = (struct bulk_cs_wrap *) us->iobuf;
unsigned int transfer_length = scsi_bufflen(srb);
unsigned int residue;
int result;
int fake_sense = 0;
unsigned int cswlen;
unsigned int cbwlen = US_BULK_CB_WRAP_LEN;
/* Take care of BULK32 devices; set extra byte to 0 */
if (unlikely(us->fflags & US_FL_BULK32)) {
cbwlen = 32;
us->iobuf[31] = 0;
}
//############################指令階段############################
/* set up the command wrapper */
bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
bcb->DataTransferLength = cpu_to_le32(transfer_length);
bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ?
US_BULK_FLAG_IN : 0;
bcb->Tag = ++us->tag;
bcb->Lun = srb->device->lun;
if (us->fflags & US_FL_SCM_MULT_TARG)
bcb->Lun |= srb->device->id << 4;
bcb->Length = srb->cmd_len;
/* copy the command payload */
memset(bcb->CDB, 0, sizeof(bcb->CDB));
memcpy(bcb->CDB, srb->cmnd, bcb->Length);
/* send it to out endpoint */
US_DEBUGP("Bulk Command S 0x%x T 0x%x L %d F %d Trg %d LUN %d CL %d\n",
le32_to_cpu(bcb->Signature), bcb->Tag,
le32_to_cpu(bcb->DataTransferLength), bcb->Flags,
(bcb->Lun >> 4), (bcb->Lun & 0x0F),
bcb->Length);
result = usb_stor_bulk_transfer_buf(us, us->send_bulk_pipe,
bcb, cbwlen, NULL);
US_DEBUGP("Bulk command transfer result=%d\n", result);
if (result != USB_STOR_XFER_GOOD)
return USB_STOR_TRANSPORT_ERROR;
/* DATA STAGE */
/* send/receive data payload, if there is any */
/* Some USB-IDE converter chips need a 100us delay between the
* command phase and the data phase. Some devices need a little
* more than that, probably because of clock rate inaccuracies. */
if (unlikely(us->fflags & US_FL_GO_SLOW))
udelay(125);
//############################資料階段############################
if (transfer_length) {
unsigned int pipe = srb->sc_data_direction == DMA_FROM_DEVICE ?
us->recv_bulk_pipe : us->send_bulk_pipe;
result = usb_stor_bulk_srb(us, pipe, srb);
// +-- usb_stor_bulk_transfer_sglist(us, pipe, scsi_sglist(srb),
// scsi_sg_count(srb), scsi_bufflen(srb),
// &partial);
// +-- usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
// sg, num_sg, length, GFP_NOIO);
// +-- usb_sg_wait(&us->current_sg);
// +-- return interpret_urb_result(us, pipe, length, result,
// us->current_sg.bytes);
// +-- scsi_set_resid(srb, scsi_bufflen(srb) - partial);
US_DEBUGP("Bulk data transfer result 0x%x\n", result);
if (result == USB_STOR_XFER_ERROR)
return USB_STOR_TRANSPORT_ERROR;
/* If the device tried to send back more data than the
* amount requested, the spec requires us to transfer
* the CSW anyway. Since there's no point retrying the
* the command, we'll return fake sense data indicating
* Illegal Request, Invalid Field in CDB.
*/
if (result == USB_STOR_XFER_LONG)
fake_sense = 1;
}
/* See flow chart on pg 15 of the Bulk Only Transport spec for
* an explanation of how this code works.
*/
//############################狀态階段############################
/* get CSW for device status */
US_DEBUGP("Attempting to get CSW...\n");
result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
bcs, US_BULK_CS_WRAP_LEN, &cswlen);
/* Some broken devices add unnecessary zero-length packets to the
* end of their data transfers. Such packets show up as 0-length
* CSWs. If we encounter such a thing, try to read the CSW again.
*/
if (result == USB_STOR_XFER_SHORT && cswlen == 0) {
US_DEBUGP("Received 0-length CSW; retrying...\n");
result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
bcs, US_BULK_CS_WRAP_LEN, &cswlen);
}
/* did the attempt to read the CSW fail? */
if (result == USB_STOR_XFER_STALLED) {
/* get the status again */
US_DEBUGP("Attempting to get CSW (2nd try)...\n");
result = usb_stor_bulk_transfer_buf(us, us->recv_bulk_pipe,
bcs, US_BULK_CS_WRAP_LEN, NULL);
}
/* if we still have a failure at this point, we're in trouble */
US_DEBUGP("Bulk status result = %d\n", result);
if (result != USB_STOR_XFER_GOOD)
return USB_STOR_TRANSPORT_ERROR;
/* check bulk status */
residue = le32_to_cpu(bcs->Residue);
US_DEBUGP("Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
le32_to_cpu(bcs->Signature), bcs->Tag,
residue, bcs->Status);
if (!(bcs->Tag == us->tag || (us->fflags & US_FL_BULK_IGNORE_TAG)) ||
bcs->Status > US_BULK_STAT_PHASE) {
US_DEBUGP("Bulk logical error\n");
return USB_STOR_TRANSPORT_ERROR;
}
/* Some broken devices report odd signatures, so we do not check them
* for validity against the spec. We store the first one we see,
* and check subsequent transfers for validity against this signature.
*/
if (!us->bcs_signature) {
us->bcs_signature = bcs->Signature;
if (us->bcs_signature != cpu_to_le32(US_BULK_CS_SIGN))
US_DEBUGP("Learnt BCS signature 0x%08X\n",
le32_to_cpu(us->bcs_signature));
} else if (bcs->Signature != us->bcs_signature) {
US_DEBUGP("Signature mismatch: got %08X, expecting %08X\n",
le32_to_cpu(bcs->Signature),
le32_to_cpu(us->bcs_signature));
return USB_STOR_TRANSPORT_ERROR;
}
/* try to compute the actual residue, based on how much data
* was really transferred and what the device tells us */
if (residue && !(us->fflags & US_FL_IGNORE_RESIDUE)) {
/* Heuristically detect devices that generate bogus residues
* by seeing what happens with INQUIRY and READ CAPACITY
* commands.
*/
if (bcs->Status == US_BULK_STAT_OK &&
scsi_get_resid(srb) == 0 &&
((srb->cmnd[0] == INQUIRY && transfer_length == 36) ||
(srb->cmnd[0] == READ_CAPACITY && transfer_length == 8)))
{
us->fflags |= US_FL_IGNORE_RESIDUE;
} else {
residue = min(residue, transfer_length);
scsi_set_resid(srb, max(scsi_get_resid(srb),(int) residue));
}
}
/* based on the status code, we report good or bad */
switch (bcs->Status) {
case US_BULK_STAT_OK:
/* device babbled -- return fake sense data */
if (fake_sense) {
memcpy(srb->sense_buffer, usb_stor_sense_invalidCDB,
sizeof(usb_stor_sense_invalidCDB));
return USB_STOR_TRANSPORT_NO_SENSE;
}
/* command good -- note that data could be short */
return USB_STOR_TRANSPORT_GOOD;
case US_BULK_STAT_FAIL:
/* command failed */
return USB_STOR_TRANSPORT_FAILED;
case US_BULK_STAT_PHASE:
/* phase error -- note that a transport reset will be
* invoked by the invoke_transport() function
*/
return USB_STOR_TRANSPORT_ERROR;
}
/* we should never get here, but if we do, we're in trouble */
return USB_STOR_TRANSPORT_ERROR;
}
EXPORT_SYMBOL_GPL(usb_stor_Bulk_transport);
static int command_abort(struct scsi_cmnd *srb)
{
struct us_data *us = host_to_us(srb->device->host);
US_DEBUGP("%s called\n", __func__);
/* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
* bits are protected by the host lock. */
scsi_lock(us_to_host(us));
/* Is this command still active? */
if (us->srb != srb) {
scsi_unlock(us_to_host(us));
US_DEBUGP ("-- nothing to abort\n");
return FAILED;
}
/* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
* a device reset isn't already in progress (to avoid interfering
* with the reset). Note that we must retain the host lock while
* calling usb_stor_stop_transport(); otherwise it might interfere
* with an auto-reset that begins as soon as we release the lock. */
set_bit(US_FLIDX_TIMED_OUT, &us->dflags);
if (!test_bit(US_FLIDX_RESETTING, &us->dflags)) {
set_bit(US_FLIDX_ABORTING, &us->dflags);
usb_stor_stop_transport(us);
//+-- if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
// usb_unlink_urb(us->current_urb);
// }
//+-- if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
// usb_sg_cancel(&us->current_sg);
// }
}
scsi_unlock(us_to_host(us));
/* Wait for the aborted command to finish */
//在這裡等待指令完成的complete(&us->notify)
wait_for_completion(&us->notify);
return SUCCESS;
}
