Revision ec057595cb3fb339e692898bedccd566160ba086 authored by Linus Torvalds on 06 December 2019, 20:40:35 UTC, committed by Linus Torvalds on 06 December 2019, 20:40:35 UTC
Similarly to commit 8f868d68d335 ("pipe: Fix missing mask update after pipe_wait()") this fixes a case where the pipe rewrite ended up caching the pipe state incorrectly over a pipe lock drop event. It wasn't quite as obvious, because you needed to splice data from a pipe to a file, which is a fairly unusual operation, but it's completely wrong. Make sure we load the pipe head/tail/size information only after we've waited for there to be data in the pipe. While in that file, also make one of the splice helper functions use the canonical arghument order for pipe_empty(). That's syntactic - pipe emptiness is just that head and tail are equal, and thus mixing up head and tail doesn't really matter. It's still wrong, though. Reported-by: David Sterba <dsterba@suse.cz> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 7ada90e
range.c
// SPDX-License-Identifier: GPL-2.0
/*
* Range add and subtract
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sort.h>
#include <linux/string.h>
#include <linux/range.h>
int add_range(struct range *range, int az, int nr_range, u64 start, u64 end)
{
if (start >= end)
return nr_range;
/* Out of slots: */
if (nr_range >= az)
return nr_range;
range[nr_range].start = start;
range[nr_range].end = end;
nr_range++;
return nr_range;
}
int add_range_with_merge(struct range *range, int az, int nr_range,
u64 start, u64 end)
{
int i;
if (start >= end)
return nr_range;
/* get new start/end: */
for (i = 0; i < nr_range; i++) {
u64 common_start, common_end;
if (!range[i].end)
continue;
common_start = max(range[i].start, start);
common_end = min(range[i].end, end);
if (common_start > common_end)
continue;
/* new start/end, will add it back at last */
start = min(range[i].start, start);
end = max(range[i].end, end);
memmove(&range[i], &range[i + 1],
(nr_range - (i + 1)) * sizeof(range[i]));
range[nr_range - 1].start = 0;
range[nr_range - 1].end = 0;
nr_range--;
i--;
}
/* Need to add it: */
return add_range(range, az, nr_range, start, end);
}
void subtract_range(struct range *range, int az, u64 start, u64 end)
{
int i, j;
if (start >= end)
return;
for (j = 0; j < az; j++) {
if (!range[j].end)
continue;
if (start <= range[j].start && end >= range[j].end) {
range[j].start = 0;
range[j].end = 0;
continue;
}
if (start <= range[j].start && end < range[j].end &&
range[j].start < end) {
range[j].start = end;
continue;
}
if (start > range[j].start && end >= range[j].end &&
range[j].end > start) {
range[j].end = start;
continue;
}
if (start > range[j].start && end < range[j].end) {
/* Find the new spare: */
for (i = 0; i < az; i++) {
if (range[i].end == 0)
break;
}
if (i < az) {
range[i].end = range[j].end;
range[i].start = end;
} else {
pr_err("%s: run out of slot in ranges\n",
__func__);
}
range[j].end = start;
continue;
}
}
}
static int cmp_range(const void *x1, const void *x2)
{
const struct range *r1 = x1;
const struct range *r2 = x2;
if (r1->start < r2->start)
return -1;
if (r1->start > r2->start)
return 1;
return 0;
}
int clean_sort_range(struct range *range, int az)
{
int i, j, k = az - 1, nr_range = az;
for (i = 0; i < k; i++) {
if (range[i].end)
continue;
for (j = k; j > i; j--) {
if (range[j].end) {
k = j;
break;
}
}
if (j == i)
break;
range[i].start = range[k].start;
range[i].end = range[k].end;
range[k].start = 0;
range[k].end = 0;
k--;
}
/* count it */
for (i = 0; i < az; i++) {
if (!range[i].end) {
nr_range = i;
break;
}
}
/* sort them */
sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
return nr_range;
}
void sort_range(struct range *range, int nr_range)
{
/* sort them */
sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
}
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