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[PATCH] USB Gadget: file_storage: remove "volatile" declarations
This patch (as612) removes the "volatile" declarations from the file-storage gadget. It turns out that they aren't needed for anything much; adding a few memory barriers does a sufficient job. The patch also removes a wait_queue. Not much point having a queue when only one task is ever going to be on it! Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern
Greg Kroah-Hartman
parent
bd39b7f195
commit
a21d4fed4b
@ -239,7 +239,6 @@
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#include <linux/string.h>
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#include <linux/suspend.h>
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#include <linux/utsname.h>
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#include <linux/wait.h>
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#include <linux/usb_ch9.h>
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#include <linux/usb_gadget.h>
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@ -251,7 +250,7 @@
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#define DRIVER_DESC "File-backed Storage Gadget"
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#define DRIVER_NAME "g_file_storage"
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#define DRIVER_VERSION "20 October 2004"
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#define DRIVER_VERSION "28 November 2005"
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static const char longname[] = DRIVER_DESC;
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static const char shortname[] = DRIVER_NAME;
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@ -588,7 +587,7 @@ enum fsg_buffer_state {
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struct fsg_buffhd {
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void *buf;
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dma_addr_t dma;
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volatile enum fsg_buffer_state state;
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enum fsg_buffer_state state;
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struct fsg_buffhd *next;
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/* The NetChip 2280 is faster, and handles some protocol faults
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@ -597,9 +596,9 @@ struct fsg_buffhd {
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unsigned int bulk_out_intended_length;
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struct usb_request *inreq;
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volatile int inreq_busy;
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int inreq_busy;
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struct usb_request *outreq;
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volatile int outreq_busy;
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int outreq_busy;
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};
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enum fsg_state {
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@ -637,11 +636,11 @@ struct fsg_dev {
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struct usb_ep *ep0; // Handy copy of gadget->ep0
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struct usb_request *ep0req; // For control responses
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volatile unsigned int ep0_req_tag;
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unsigned int ep0_req_tag;
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const char *ep0req_name;
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struct usb_request *intreq; // For interrupt responses
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volatile int intreq_busy;
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int intreq_busy;
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struct fsg_buffhd *intr_buffhd;
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unsigned int bulk_out_maxpacket;
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@ -671,7 +670,6 @@ struct fsg_dev {
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struct fsg_buffhd *next_buffhd_to_drain;
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struct fsg_buffhd buffhds[NUM_BUFFERS];
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wait_queue_head_t thread_wqh;
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int thread_wakeup_needed;
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struct completion thread_notifier;
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struct task_struct *thread_task;
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@ -1076,11 +1074,13 @@ static int populate_config_buf(struct usb_gadget *gadget,
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/* These routines may be called in process context or in_irq */
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/* Caller must hold fsg->lock */
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static void wakeup_thread(struct fsg_dev *fsg)
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{
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/* Tell the main thread that something has happened */
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fsg->thread_wakeup_needed = 1;
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wake_up_all(&fsg->thread_wqh);
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if (fsg->thread_task)
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wake_up_process(fsg->thread_task);
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}
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@ -1167,11 +1167,12 @@ static void bulk_in_complete(struct usb_ep *ep, struct usb_request *req)
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usb_ep_fifo_flush(ep);
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/* Hold the lock while we update the request and buffer states */
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smp_wmb();
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spin_lock(&fsg->lock);
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bh->inreq_busy = 0;
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bh->state = BUF_STATE_EMPTY;
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spin_unlock(&fsg->lock);
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wakeup_thread(fsg);
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spin_unlock(&fsg->lock);
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}
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static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
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@ -1188,11 +1189,12 @@ static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
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usb_ep_fifo_flush(ep);
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/* Hold the lock while we update the request and buffer states */
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smp_wmb();
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spin_lock(&fsg->lock);
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bh->outreq_busy = 0;
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bh->state = BUF_STATE_FULL;
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spin_unlock(&fsg->lock);
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wakeup_thread(fsg);
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spin_unlock(&fsg->lock);
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}
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@ -1209,11 +1211,12 @@ static void intr_in_complete(struct usb_ep *ep, struct usb_request *req)
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usb_ep_fifo_flush(ep);
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/* Hold the lock while we update the request and buffer states */
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smp_wmb();
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spin_lock(&fsg->lock);
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fsg->intreq_busy = 0;
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bh->state = BUF_STATE_EMPTY;
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spin_unlock(&fsg->lock);
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wakeup_thread(fsg);
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spin_unlock(&fsg->lock);
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}
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#else
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@ -1264,8 +1267,8 @@ static void received_cbi_adsc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
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fsg->cbbuf_cmnd_size = req->actual;
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memcpy(fsg->cbbuf_cmnd, req->buf, fsg->cbbuf_cmnd_size);
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spin_unlock(&fsg->lock);
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wakeup_thread(fsg);
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spin_unlock(&fsg->lock);
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}
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#else
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@ -1517,8 +1520,8 @@ static int fsg_setup(struct usb_gadget *gadget,
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/* Use this for bulk or interrupt transfers, not ep0 */
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static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
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struct usb_request *req, volatile int *pbusy,
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volatile enum fsg_buffer_state *state)
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struct usb_request *req, int *pbusy,
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enum fsg_buffer_state *state)
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{
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int rc;
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@ -1526,8 +1529,11 @@ static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
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dump_msg(fsg, "bulk-in", req->buf, req->length);
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else if (ep == fsg->intr_in)
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dump_msg(fsg, "intr-in", req->buf, req->length);
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spin_lock_irq(&fsg->lock);
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*pbusy = 1;
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*state = BUF_STATE_BUSY;
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spin_unlock_irq(&fsg->lock);
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rc = usb_ep_queue(ep, req, GFP_KERNEL);
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if (rc != 0) {
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*pbusy = 0;
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@ -1547,14 +1553,23 @@ static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
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static int sleep_thread(struct fsg_dev *fsg)
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{
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int rc;
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int rc = 0;
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/* Wait until a signal arrives or we are woken up */
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rc = wait_event_interruptible(fsg->thread_wqh,
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fsg->thread_wakeup_needed);
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for (;;) {
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try_to_freeze();
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set_current_state(TASK_INTERRUPTIBLE);
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if (signal_pending(current)) {
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rc = -EINTR;
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break;
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}
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if (fsg->thread_wakeup_needed)
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break;
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schedule();
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}
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__set_current_state(TASK_RUNNING);
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fsg->thread_wakeup_needed = 0;
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try_to_freeze();
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return (rc ? -EINTR : 0);
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return rc;
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}
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@ -1791,6 +1806,7 @@ static int do_write(struct fsg_dev *fsg)
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if (bh->state == BUF_STATE_EMPTY && !get_some_more)
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break; // We stopped early
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if (bh->state == BUF_STATE_FULL) {
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smp_rmb();
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fsg->next_buffhd_to_drain = bh->next;
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bh->state = BUF_STATE_EMPTY;
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@ -2359,6 +2375,7 @@ static int throw_away_data(struct fsg_dev *fsg)
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/* Throw away the data in a filled buffer */
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if (bh->state == BUF_STATE_FULL) {
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smp_rmb();
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bh->state = BUF_STATE_EMPTY;
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fsg->next_buffhd_to_drain = bh->next;
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@ -3024,6 +3041,7 @@ static int get_next_command(struct fsg_dev *fsg)
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if ((rc = sleep_thread(fsg)) != 0)
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return rc;
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}
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smp_rmb();
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rc = received_cbw(fsg, bh);
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bh->state = BUF_STATE_EMPTY;
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@ -4072,7 +4090,6 @@ static int __init fsg_alloc(void)
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spin_lock_init(&fsg->lock);
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init_rwsem(&fsg->filesem);
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kref_init(&fsg->ref);
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init_waitqueue_head(&fsg->thread_wqh);
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init_completion(&fsg->thread_notifier);
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the_fsg = fsg;
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