From dd05add7b2b6004c5fa3a1f276f56d8668f86b65 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Sat, 26 Sep 2026 19:20:30 -0300 Subject: netfs: zero the tail of a short DIO/unbuffered read The buffered read collector zero-fills the tail of a short read that stops below the inode's i_size (netfs_clear_unread()), so a read that races an extending write still returns the expected number of bytes. The non-buffered collector path does no such thing: it just records how much was transferred. Add the same zero-fill for the non-buffered case, gated on NETFS_SREQ_CLEAR_TAIL: a subreq's source sets that flag when a short result from it is known to be safe to treat as a hole, as opposed to NETFS_SREQ_HIT_EOF, which means the read genuinely ran off the end of the file and should be reported short as-is. Only CLEAR_TAIL should zero-fill here; a real EOF must stay a real short read. No source currently sets CLEAR_TAIL on an unbuffered/DIO subrequest, so this is inert on its own -- a following change teaches cifs to set it in the one case that needs it. Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item") Reviewed-by: David Howells Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- drivers/comedi/proc.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 drivers/comedi/proc.c (limited to 'drivers/comedi/proc.c') diff --git a/drivers/comedi/proc.c b/drivers/comedi/proc.c new file mode 100644 index 000000000..2e4496633 --- /dev/null +++ b/drivers/comedi/proc.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * /proc interface for comedi + * + * COMEDI - Linux Control and Measurement Device Interface + * Copyright (C) 1998 David A. Schleef + */ + +/* + * This is some serious bloatware. + * + * Taken from Dave A.'s PCL-711 driver, 'cuz I thought it + * was cool. + */ + +#include +#include "comedi_internal.h" +#include +#include + +static int comedi_read(struct seq_file *m, void *v) +{ + int i; + int devices_q = 0; + struct comedi_driver *driv; + + seq_printf(m, "comedi version " COMEDI_RELEASE "\nformat string: %s\n", + "\"%2d: %-20s %-20s %4d\", i, driver_name, board_name, n_subdevices"); + + for (i = 0; i < COMEDI_NUM_BOARD_MINORS; i++) { + struct comedi_device *dev = comedi_dev_get_from_minor(i); + + if (!dev) + continue; + + down_read(&dev->attach_lock); + if (dev->attached) { + devices_q = 1; + seq_printf(m, "%2d: %-20s %-20s %4d\n", + i, dev->driver->driver_name, + dev->board_name, dev->n_subdevices); + } + up_read(&dev->attach_lock); + comedi_dev_put(dev); + } + if (!devices_q) + seq_puts(m, "no devices\n"); + + mutex_lock(&comedi_drivers_list_lock); + for (driv = comedi_drivers; driv; driv = driv->next) { + seq_printf(m, "%s:\n", driv->driver_name); + for (i = 0; i < driv->num_names; i++) + seq_printf(m, " %s\n", + *(char **)((char *)driv->board_name + + i * driv->offset)); + + if (!driv->num_names) + seq_printf(m, " %s\n", driv->driver_name); + } + mutex_unlock(&comedi_drivers_list_lock); + + return 0; +} + +void __init comedi_proc_init(void) +{ + if (!proc_create_single("comedi", 0444, NULL, comedi_read)) + pr_warn("comedi: unable to create proc entry\n"); +} + +void comedi_proc_cleanup(void) +{ + remove_proc_entry("comedi", NULL); +} -- cgit v1.3.1