/* * Driver for USB Mass Storage compliant devices * Transport Functions Header File * * Current development and maintenance by: * (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net) * * This driver is based on the 'USB Mass Storage Class' document. This * describes in detail the protocol used to communicate with such * devices. Clearly, the designers had SCSI and ATAPI commands in * mind when they created this document. The commands are all very * similar to commands in the SCSI-II and ATAPI specifications. * * It is important to note that in a number of cases this class * exhibits class-specific exemptions from the USB specification. * Notably the usage of NAK, STALL and ACK differs from the norm, in * that they are used to communicate wait, failed and OK on commands. * * Also, for certain devices, the interrupt endpoint is used to convey * status of a command. * * Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more * information about this driver. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2, or (at your option) any * later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 675 Mass Ave, Cambridge, MA 02139, USA. */ #ifndef _TRANSPORT_H_ #define _TRANSPORT_H_ #include /* * usb_stor_bulk_transfer_xxx() return codes, in order of severity */ #define USB_STOR_XFER_GOOD 0 /* good transfer */ #define USB_STOR_XFER_SHORT 1 /* transferred less than expected */ #define USB_STOR_XFER_STALLED 2 /* endpoint stalled */ #define USB_STOR_XFER_LONG 3 /* device tried to send too much */ #define USB_STOR_XFER_ERROR 4 /* transfer died in the middle */ /* * Transport return codes */ #define USB_STOR_TRANSPORT_GOOD 0 /* Transport good, command good */ #define USB_STOR_TRANSPORT_FAILED 1 /* Transport good, command failed */ #define USB_STOR_TRANSPORT_NO_SENSE 2 /* Command failed, no auto-sense */ #define USB_STOR_TRANSPORT_ERROR 3 /* Transport bad (i.e. device dead) */ /* * We used to have USB_STOR_XFER_ABORTED and USB_STOR_TRANSPORT_ABORTED * return codes. But now the transport and low-level transfer routines * treat an abort as just another error (-ENOENT for a cancelled URB). * It is up to the invoke_transport() function to test for aborts and * distinguish them from genuine communication errors. */ /* * CBI accept device specific command */ #define US_CBI_ADSC 0 extern int usb_stor_CB_transport(struct scsi_cmnd *, struct us_data*); extern int usb_stor_CB_reset(struct us_data*); extern int usb_stor_Bulk_transport(struct scsi_cmnd *, struct us_data*); extern int usb_stor_Bulk_max_lun(struct us_data*); extern int usb_stor_Bulk_reset(struct us_data*); extern void usb_stor_invoke_transport(struct scsi_cmnd *, struct us_data*); extern void usb_stor_stop_transport(struct us_data*); extern int usb_stor_control_msg(struct us_data *us, unsigned int pipe, u8 request, u8 requesttype, u16 value, u16 index, void *data, u16 size, int timeout); extern int usb_stor_clear_halt(struct us_data *us, unsigned int pipe); extern int usb_stor_ctrl_transfer(struct us_data *us, unsigned int pipe, u8 request, u8 requesttype, u16 value, u16 index, void *data, u16 size); extern int usb_stor_bulk_transfer_buf(struct us_data *us, unsigned int pipe, void *buf, unsigned int length, unsigned int *act_len); extern int usb_stor_bulk_transfer_sg(struct us_data *us, unsigned int pipe, void *buf, unsigned int length, int use_sg, int *residual); extern int usb_stor_bulk_srb(struct us_data* us, unsigned int pipe, struct scsi_cmnd* srb); extern int usb_stor_port_reset(struct us_data *us); #endif
authorIago Abal <mail@iagoabal.eu>2017-01-11 14:00:21 +0100
committerVinod Koul <vinod.koul@intel.com>2017-01-25 15:35:11 +0530
commit91539eb1fda2d530d3b268eef542c5414e54bf1a (patch)
tree960f5ca6342ad20837aff18aad6e8ecd7da32fd6 /net/sunrpc
parent6610d0edf6dc7ee97e46ab3a538a565c79d26199 (diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'net/sunrpc')