mirror of
https://github.com/archlinuxarm/PKGBUILDs.git
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99 lines
2.4 KiB
Diff
99 lines
2.4 KiB
Diff
From d9b2000fed21f7ed990ffe7dc0b26834242e6fce Mon Sep 17 00:00:00 2001
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From: Greg Price <price@MIT.EDU>
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Date: Fri, 29 Nov 2013 15:02:33 -0500
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Subject: [PATCH 5/8] random: simplify loop in random_read
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The loop condition never changes until just before a break, so we
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might as well write it as a constant. Also since a996996dd75a
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("random: drop weird m_time/a_time manipulation") we don't do anything
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after the loop finishes, so the 'break's might as well return
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directly. Some other simplifications.
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There should be no change in behavior introduced by this commit.
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Signed-off-by: Greg Price <price@mit.edu>
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Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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---
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drivers/char/random.c | 57 ++++++++++++++++-----------------------------------
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1 file changed, 18 insertions(+), 39 deletions(-)
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diff --git a/drivers/char/random.c b/drivers/char/random.c
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index 8757d727116f..d9e8504894ee 100644
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--- a/drivers/char/random.c
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+++ b/drivers/char/random.c
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@@ -1287,53 +1287,32 @@ void rand_initialize_disk(struct gendisk *disk)
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static ssize_t
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random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
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{
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- ssize_t n, retval = 0, count = 0;
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+ ssize_t n;
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if (nbytes == 0)
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return 0;
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- while (nbytes > 0) {
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- n = nbytes;
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- if (n > SEC_XFER_SIZE)
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- n = SEC_XFER_SIZE;
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-
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- n = extract_entropy_user(&blocking_pool, buf, n);
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-
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- if (n < 0) {
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- retval = n;
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- break;
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- }
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-
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+ nbytes = min_t(size_t, nbytes, SEC_XFER_SIZE);
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+ while (1) {
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+ n = extract_entropy_user(&blocking_pool, buf, nbytes);
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+ if (n < 0)
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+ return n;
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trace_random_read(n*8, (nbytes-n)*8,
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ENTROPY_BITS(&blocking_pool),
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ENTROPY_BITS(&input_pool));
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-
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- if (n == 0) {
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- if (file->f_flags & O_NONBLOCK) {
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- retval = -EAGAIN;
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- break;
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- }
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-
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- wait_event_interruptible(random_read_wait,
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- ENTROPY_BITS(&input_pool) >=
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- random_read_wakeup_thresh);
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-
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- if (signal_pending(current)) {
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- retval = -ERESTARTSYS;
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- break;
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- }
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-
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- continue;
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- }
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-
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- count += n;
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- buf += n;
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- nbytes -= n;
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- break; /* This break makes the device work */
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- /* like a named pipe */
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+ if (n > 0)
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+ return n;
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+ /* Pool is (near) empty. Maybe wait and retry. */
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+
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+ if (file->f_flags & O_NONBLOCK)
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+ return -EAGAIN;
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+
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+ wait_event_interruptible(random_read_wait,
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+ ENTROPY_BITS(&input_pool) >=
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+ random_read_wakeup_thresh);
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+ if (signal_pending(current))
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+ return -ERESTARTSYS;
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}
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-
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- return (count ? count : retval);
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}
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static ssize_t
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--
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2.13.0
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