From ee81b3e086c907a3347b15ef219a24fc8bf900f6 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 25 Mar 2011 11:46:27 -0400 Subject: [PATCH] USB: g_file_storage: don't send padding when stall=n This patch (as1455) removes the extra padding sent by g_file_storage and g_mass_storage when the gadget wants to send less data than requested by the host and isn't allowed to halt the bulk-IN endpoint. Although the Bulk-Only Transport specification requires the padding to be present, it isn't truly needed since the transfer will be terminated by a short packet anyway. Furthermore, many existing devices don't bother to send any padding. Signed-off-by: Alan Stern Acked-By: Michal Nazarewicz CC: Roger Quadros Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/f_mass_storage.c | 54 ++++++----------------------- drivers/usb/gadget/file_storage.c | 53 +++++++--------------------- 2 files changed, 23 insertions(+), 84 deletions(-) diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c index 125587ac5d0b..98d6b39061d2 100644 --- a/drivers/usb/gadget/f_mass_storage.c +++ b/drivers/usb/gadget/f_mass_storage.c @@ -1569,37 +1569,6 @@ static int wedge_bulk_in_endpoint(struct fsg_dev *fsg) return rc; } -static int pad_with_zeros(struct fsg_dev *fsg) -{ - struct fsg_buffhd *bh = fsg->common->next_buffhd_to_fill; - u32 nkeep = bh->inreq->length; - u32 nsend; - int rc; - - bh->state = BUF_STATE_EMPTY; /* For the first iteration */ - fsg->common->usb_amount_left = nkeep + fsg->common->residue; - while (fsg->common->usb_amount_left > 0) { - - /* Wait for the next buffer to be free */ - while (bh->state != BUF_STATE_EMPTY) { - rc = sleep_thread(fsg->common); - if (rc) - return rc; - } - - nsend = min(fsg->common->usb_amount_left, FSG_BUFLEN); - memset(bh->buf + nkeep, 0, nsend - nkeep); - bh->inreq->length = nsend; - bh->inreq->zero = 0; - start_transfer(fsg, fsg->bulk_in, bh->inreq, - &bh->inreq_busy, &bh->state); - bh = fsg->common->next_buffhd_to_fill = bh->next; - fsg->common->usb_amount_left -= nsend; - nkeep = 0; - } - return 0; -} - static int throw_away_data(struct fsg_common *common) { struct fsg_buffhd *bh; @@ -1686,6 +1655,10 @@ static int finish_reply(struct fsg_common *common) if (common->data_size == 0) { /* Nothing to send */ + /* Don't know what to do if common->fsg is NULL */ + } else if (!fsg_is_set(common)) { + rc = -EIO; + /* If there's no residue, simply send the last buffer */ } else if (common->residue == 0) { bh->inreq->zero = 0; @@ -1694,24 +1667,19 @@ static int finish_reply(struct fsg_common *common) common->next_buffhd_to_fill = bh->next; /* - * For Bulk-only, if we're allowed to stall then send the - * short packet and halt the bulk-in endpoint. If we can't - * stall, pad out the remaining data with 0's. + * For Bulk-only, mark the end of the data with a short + * packet. If we are allowed to stall, halt the bulk-in + * endpoint. (Note: This violates the Bulk-Only Transport + * specification, which requires us to pad the data if we + * don't halt the endpoint. Presumably nobody will mind.) */ - } else if (common->can_stall) { + } else { bh->inreq->zero = 1; if (!start_in_transfer(common, bh)) - /* Don't know what to do if - * common->fsg is NULL */ rc = -EIO; common->next_buffhd_to_fill = bh->next; - if (common->fsg) + if (common->can_stall) rc = halt_bulk_in_endpoint(common->fsg); - } else if (fsg_is_set(common)) { - rc = pad_with_zeros(common->fsg); - } else { - /* Don't know what to do if common->fsg is NULL */ - rc = -EIO; } break; diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c index d04e0e6b019d..aebfb81f3ba4 100644 --- a/drivers/usb/gadget/file_storage.c +++ b/drivers/usb/gadget/file_storage.c @@ -1932,37 +1932,6 @@ static int wedge_bulk_in_endpoint(struct fsg_dev *fsg) return rc; } -static int pad_with_zeros(struct fsg_dev *fsg) -{ - struct fsg_buffhd *bh = fsg->next_buffhd_to_fill; - u32 nkeep = bh->inreq->length; - u32 nsend; - int rc; - - bh->state = BUF_STATE_EMPTY; // For the first iteration - fsg->usb_amount_left = nkeep + fsg->residue; - while (fsg->usb_amount_left > 0) { - - /* Wait for the next buffer to be free */ - while (bh->state != BUF_STATE_EMPTY) { - rc = sleep_thread(fsg); - if (rc) - return rc; - } - - nsend = min(fsg->usb_amount_left, (u32) mod_data.buflen); - memset(bh->buf + nkeep, 0, nsend - nkeep); - bh->inreq->length = nsend; - bh->inreq->zero = 0; - start_transfer(fsg, fsg->bulk_in, bh->inreq, - &bh->inreq_busy, &bh->state); - bh = fsg->next_buffhd_to_fill = bh->next; - fsg->usb_amount_left -= nsend; - nkeep = 0; - } - return 0; -} - static int throw_away_data(struct fsg_dev *fsg) { struct fsg_buffhd *bh; @@ -2066,18 +2035,20 @@ static int finish_reply(struct fsg_dev *fsg) } } - /* For Bulk-only, if we're allowed to stall then send the - * short packet and halt the bulk-in endpoint. If we can't - * stall, pad out the remaining data with 0's. */ + /* + * For Bulk-only, mark the end of the data with a short + * packet. If we are allowed to stall, halt the bulk-in + * endpoint. (Note: This violates the Bulk-Only Transport + * specification, which requires us to pad the data if we + * don't halt the endpoint. Presumably nobody will mind.) + */ else { - if (mod_data.can_stall) { - bh->inreq->zero = 1; - start_transfer(fsg, fsg->bulk_in, bh->inreq, - &bh->inreq_busy, &bh->state); - fsg->next_buffhd_to_fill = bh->next; + bh->inreq->zero = 1; + start_transfer(fsg, fsg->bulk_in, bh->inreq, + &bh->inreq_busy, &bh->state); + fsg->next_buffhd_to_fill = bh->next; + if (mod_data.can_stall) rc = halt_bulk_in_endpoint(fsg); - } else - rc = pad_with_zeros(fsg); } break; -- 2.20.1