From patchwork Wed Jan 18 20:31:11 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: w1: ds2490: USB transfer buffers need to be DMAable From: "Maciej S. Szmigiero" X-Patchwork-Id: 9524693 Message-Id: <5ba98814-d0b0-fbd4-d631-eda3472f4017@maciej.szmigiero.name> To: Evgeniy Polyakov Cc: linux-kernel Date: Wed, 18 Jan 2017 21:31:11 +0100 ds2490 driver was doing USB transfers from / to buffers on a stack. This is not permitted and made the driver non-working with vmapped stacks. Since all these transfers are done under the same bus_mutex lock we can simply use shared buffers in a device private structure for two most common of them. While we are at it, let's also fix a comparison between int and size_t in ds9490r_search() which made the driver spin in this function if state register get requests were failing. Signed-off-by: Maciej S. Szmigiero Cc: stable@vger.kernel.org --- drivers/w1/masters/ds2490.c | 142 ++++++++++++++++++++++++++------------------ 1 file changed, 84 insertions(+), 58 deletions(-) diff --git a/drivers/w1/masters/ds2490.c b/drivers/w1/masters/ds2490.c index 049a884a756f..59d74d1b47a8 100644 --- a/drivers/w1/masters/ds2490.c +++ b/drivers/w1/masters/ds2490.c @@ -153,6 +153,9 @@ struct ds_device */ u16 spu_bit; + u8 st_buf[ST_SIZE]; + u8 byte_buf; + struct w1_bus_master master; }; @@ -174,7 +177,6 @@ struct ds_status u8 data_in_buffer_status; u8 reserved1; u8 reserved2; - }; static struct usb_device_id ds_id_table [] = { @@ -244,28 +246,6 @@ static int ds_send_control(struct ds_device *dev, u16 value, u16 index) return err; } -static int ds_recv_status_nodump(struct ds_device *dev, struct ds_status *st, - unsigned char *buf, int size) -{ - int count, err; - - memset(st, 0, sizeof(*st)); - - count = 0; - err = usb_interrupt_msg(dev->udev, usb_rcvintpipe(dev->udev, - dev->ep[EP_STATUS]), buf, size, &count, 1000); - if (err < 0) { - pr_err("Failed to read 1-wire data from 0x%x: err=%d.\n", - dev->ep[EP_STATUS], err); - return err; - } - - if (count >= sizeof(*st)) - memcpy(st, buf, sizeof(*st)); - - return count; -} - static inline void ds_print_msg(unsigned char *buf, unsigned char *str, int off) { pr_info("%45s: %8x\n", str, buf[off]); @@ -324,6 +304,35 @@ static void ds_dump_status(struct ds_device *dev, unsigned char *buf, int count) } } +static int ds_recv_status(struct ds_device *dev, struct ds_status *st, + bool dump) +{ + int count, err; + + if (st) + memset(st, 0, sizeof(*st)); + + count = 0; + err = usb_interrupt_msg(dev->udev, + usb_rcvintpipe(dev->udev, + dev->ep[EP_STATUS]), + dev->st_buf, sizeof(dev->st_buf), + &count, 1000); + if (err < 0) { + pr_err("Failed to read 1-wire data from 0x%x: err=%d.\n", + dev->ep[EP_STATUS], err); + return err; + } + + if (dump) + ds_dump_status(dev, dev->st_buf, count); + + if (st && count >= sizeof(*st)) + memcpy(st, dev->st_buf, sizeof(*st)); + + return count; +} + static void ds_reset_device(struct ds_device *dev) { ds_send_control_cmd(dev, CTL_RESET_DEVICE, 0); @@ -344,7 +353,6 @@ static void ds_reset_device(struct ds_device *dev) static int ds_recv_data(struct ds_device *dev, unsigned char *buf, int size) { int count, err; - struct ds_status st; /* Careful on size. If size is less than what is available in * the input buffer, the device fails the bulk transfer and @@ -359,14 +367,9 @@ static int ds_recv_data(struct ds_device *dev, unsigned char *buf, int size) err = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]), buf, size, &count, 1000); if (err < 0) { - u8 buf[ST_SIZE]; - int count; - pr_info("Clearing ep0x%x.\n", dev->ep[EP_DATA_IN]); usb_clear_halt(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN])); - - count = ds_recv_status_nodump(dev, &st, buf, sizeof(buf)); - ds_dump_status(dev, buf, count); + ds_recv_status(dev, NULL, true); return err; } @@ -404,7 +407,6 @@ int ds_stop_pulse(struct ds_device *dev, int limit) { struct ds_status st; int count = 0, err = 0; - u8 buf[ST_SIZE]; do { err = ds_send_control(dev, CTL_HALT_EXE_IDLE, 0); @@ -413,7 +415,7 @@ int ds_stop_pulse(struct ds_device *dev, int limit) err = ds_send_control(dev, CTL_RESUME_EXE, 0); if (err) break; - err = ds_recv_status_nodump(dev, &st, buf, sizeof(buf)); + err = ds_recv_status(dev, &st, false); if (err) break; @@ -456,18 +458,17 @@ int ds_detect(struct ds_device *dev, struct ds_status *st) static int ds_wait_status(struct ds_device *dev, struct ds_status *st) { - u8 buf[ST_SIZE]; int err, count = 0; do { st->status = 0; - err = ds_recv_status_nodump(dev, st, buf, sizeof(buf)); + err = ds_recv_status(dev, st, false); #if 0 if (err >= 0) { int i; printk("0x%x: count=%d, status: ", dev->ep[EP_STATUS], err); for (i=0; ist_buf[i]); printk("\n"); } #endif @@ -485,7 +486,7 @@ static int ds_wait_status(struct ds_device *dev, struct ds_status *st) * can do something with it). */ if (err > 16 || count >= 100 || err < 0) - ds_dump_status(dev, buf, err); + ds_dump_status(dev, dev->st_buf, err); /* Extended data isn't an error. Well, a short is, but the dump * would have already told the user that and we can't do anything @@ -608,7 +609,6 @@ static int ds_write_byte(struct ds_device *dev, u8 byte) { int err; struct ds_status st; - u8 rbyte; err = ds_send_control(dev, COMM_BYTE_IO | COMM_IM | dev->spu_bit, byte); if (err) @@ -621,11 +621,11 @@ static int ds_write_byte(struct ds_device *dev, u8 byte) if (err) return err; - err = ds_recv_data(dev, &rbyte, sizeof(rbyte)); + err = ds_recv_data(dev, &dev->byte_buf, 1); if (err < 0) return err; - return !(byte == rbyte); + return !(byte == dev->byte_buf); } static int ds_read_byte(struct ds_device *dev, u8 *byte) @@ -712,7 +712,6 @@ static void ds9490r_search(void *data, struct w1_master *master, int err; u16 value, index; struct ds_status st; - u8 st_buf[ST_SIZE]; int search_limit; int found = 0; int i; @@ -724,7 +723,12 @@ static void ds9490r_search(void *data, struct w1_master *master, /* FIFO 128 bytes, bulk packet size 64, read a multiple of the * packet size. */ - u64 buf[2*64/8]; + const size_t bufsize = 2 * 64; + u64 *buf; + + buf = kmalloc(bufsize, GFP_KERNEL); + if (!buf) + return; mutex_lock(&master->bus_mutex); @@ -745,10 +749,9 @@ static void ds9490r_search(void *data, struct w1_master *master, do { schedule_timeout(jtime); - if (ds_recv_status_nodump(dev, &st, st_buf, sizeof(st_buf)) < - sizeof(st)) { + err = ds_recv_status(dev, &st, false); + if (err < 0 || err < sizeof(st)) break; - } if (st.data_in_buffer_status) { /* Bulk in can receive partial ids, but when it does @@ -758,7 +761,7 @@ static void ds9490r_search(void *data, struct w1_master *master, * bulk without first checking if status says there * is data to read. */ - err = ds_recv_data(dev, (u8 *)buf, sizeof(buf)); + err = ds_recv_data(dev, (u8 *)buf, bufsize); if (err < 0) break; for (i = 0; i < err/8; ++i) { @@ -794,9 +797,14 @@ static void ds9490r_search(void *data, struct w1_master *master, } search_out: mutex_unlock(&master->bus_mutex); + kfree(buf); } #if 0 +/* + * FIXME: if this disabled code is ever used in the future all ds_send_data() + * calls must be changed to use a DMAable buffer. + */ static int ds_match_access(struct ds_device *dev, u64 init) { int err; @@ -845,13 +853,12 @@ static int ds_set_path(struct ds_device *dev, u64 init) static u8 ds9490r_touch_bit(void *data, u8 bit) { - u8 ret; struct ds_device *dev = data; - if (ds_touch_bit(dev, bit, &ret)) + if (ds_touch_bit(dev, bit, &dev->byte_buf)) return 0; - return ret; + return dev->byte_buf; } #if 0 @@ -866,13 +873,12 @@ static u8 ds9490r_read_bit(void *data) { struct ds_device *dev = data; int err; - u8 bit = 0; - err = ds_touch_bit(dev, 1, &bit); + err = ds_touch_bit(dev, 1, &dev->byte_buf); if (err) return 0; - return bit & 1; + return dev->byte_buf & 1; } #endif @@ -887,32 +893,52 @@ static u8 ds9490r_read_byte(void *data) { struct ds_device *dev = data; int err; - u8 byte = 0; - err = ds_read_byte(dev, &byte); + err = ds_read_byte(dev, &dev->byte_buf); if (err) return 0; - return byte; + return dev->byte_buf; } static void ds9490r_write_block(void *data, const u8 *buf, int len) { struct ds_device *dev = data; + u8 *tbuf; + + if (len <= 0) + return; + + tbuf = kmalloc(len, GFP_KERNEL); + if (!tbuf) + return; - ds_write_block(dev, (u8 *)buf, len); + memcpy(tbuf, buf, len); + ds_write_block(dev, tbuf, len); + + kfree(tbuf); } static u8 ds9490r_read_block(void *data, u8 *buf, int len) { struct ds_device *dev = data; int err; + u8 *tbuf; - err = ds_read_block(dev, buf, len); - if (err < 0) + if (len <= 0) + return 0; + + tbuf = kmalloc(len, GFP_KERNEL); + if (!tbuf) return 0; - return len; + err = ds_read_block(dev, tbuf, len); + if (err >= 0) + memcpy(buf, tbuf, len); + + kfree(tbuf); + + return err >= 0 ? len : 0; } static u8 ds9490r_reset(void *data)