From: Yuyang Du <duyuyang@gmail.com>
To: peterz@infradead.org, will.deacon@arm.com, mingo@kernel.org
Cc: bvanassche@acm.org, ming.lei@redhat.com,
linux-kernel@vger.kernel.org, Yuyang Du <duyuyang@gmail.com>
Subject: [PATCH v2 03/19] locking/lockdep: Adjust lock usage bit character checks
Date: Mon, 18 Mar 2019 16:57:17 +0800 [thread overview]
Message-ID: <20190318085733.3143-4-duyuyang@gmail.com> (raw)
In-Reply-To: <20190318085733.3143-1-duyuyang@gmail.com>
The lock usage bit characters are defined and determined with tricks. Use a
macro and add some explanation to make it a bit clearer. Then adjust the
logic to check the usage, which optimizes the code a bit.
No functional change.
Signed-off-by: Yuyang Du <duyuyang@gmail.com>
---
kernel/locking/lockdep.c | 21 ++++++++++++++++-----
kernel/locking/lockdep_internals.h | 1 +
2 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 1c5e947..d5b66cf 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -514,15 +514,26 @@ static inline unsigned long lock_flag(enum lock_usage_bit bit)
static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
{
+ /*
+ * The usage character defaults to '.' (i.e., irqs disabled and not in
+ * irq context), which is the safest usage category.
+ */
char c = '.';
- if (class->usage_mask & lock_flag(bit + 2))
+ /*
+ * The order of the following usage checks matters, which will
+ * result in the outcome character as follows:
+ *
+ * - '+': irq is enabled and not in irq context
+ * - '-': in irq context and irq is disabled
+ * - '?': in irq context and irq is enabled
+ */
+ if (class->usage_mask & lock_flag(bit + LOCK_USAGE_TO_ENABLED_STEP)) {
c = '+';
- if (class->usage_mask & lock_flag(bit)) {
- c = '-';
- if (class->usage_mask & lock_flag(bit + 2))
+ if (class->usage_mask & lock_flag(bit))
c = '?';
- }
+ } else if (class->usage_mask & lock_flag(bit))
+ c = '-';
return c;
}
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index d4c1974..2fd31d5 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -25,6 +25,7 @@ enum lock_usage_bit {
#define LOCK_USAGE_READ_MASK 1
#define LOCK_USAGE_DIR_MASK 2
#define LOCK_USAGE_STATE_MASK (~(LOCK_USAGE_READ_MASK | LOCK_USAGE_DIR_MASK))
+#define LOCK_USAGE_TO_ENABLED_STEP 2
/*
* Usage-state bitmasks:
--
1.8.3.1
next prev parent reply other threads:[~2019-03-18 8:57 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 8:57 [PATCH v2 00/19] locking/lockdep: Add comments and make some code Yuyang Du
2019-03-18 8:57 ` [PATCH v2 01/19] locking/lockdep: Change all print_*() return type to void Yuyang Du
2019-03-18 9:45 ` Joe Perches
2019-03-19 3:28 ` Yuyang Du
2019-03-19 16:30 ` Bart Van Assche
2019-03-18 8:57 ` [PATCH v2 02/19] locking/lockdep: Add description and explanation in lockdep design doc Yuyang Du
2019-03-18 8:57 ` Yuyang Du [this message]
2019-03-18 8:57 ` [PATCH v2 04/19] locking/lockdep: Remove useless conditional macro Yuyang Du
2019-03-18 8:57 ` [PATCH v2 05/19] locking/lockdep: Adjust indents for function definitions Yuyang Du
2019-03-19 16:33 ` Bart Van Assche
2019-03-19 16:36 ` Peter Zijlstra
2019-03-18 8:57 ` [PATCH v2 06/19] locking/lockdep: Print the right depth for chain key colission Yuyang Du
2019-03-18 8:57 ` [PATCH v2 07/19] locking/lockdep: Update obsolete struct field description Yuyang Du
2019-03-19 16:35 ` Bart Van Assche
2019-03-19 16:44 ` Peter Zijlstra
2019-03-18 8:57 ` [PATCH v2 08/19] locking/lockdep: Use lockdep_init_task for task initiation consistently Yuyang Du
2019-03-18 8:57 ` [PATCH v2 09/19] locking/lockdep: Define INITIAL_CHAIN_KEY for chain keys to start with Yuyang Du
2019-03-18 8:57 ` [PATCH v2 10/19] locking/lockdep: Change the range of class_idx in held_lock struct Yuyang Du
2019-03-18 8:57 ` [PATCH v2 11/19] locking/lockdep: Remove unused argument in validate_chain() Yuyang Du
2019-03-19 16:45 ` Bart Van Assche
2019-03-18 8:57 ` [PATCH v2 12/19] locking/lockdep: Update comment Yuyang Du
2019-03-18 8:57 ` [PATCH v2 13/19] locking/lockdep: Remove unnecessary function pointer argument Yuyang Du
2019-03-19 16:48 ` Bart Van Assche
2019-03-18 8:57 ` [PATCH v2 14/19] locking/lockdep: Change type of the element field in circular_queue Yuyang Du
2019-03-19 16:50 ` Bart Van Assche
2019-03-19 16:51 ` Bart Van Assche
2019-03-18 8:57 ` [PATCH v2 15/19] locking/lockdep: Remove __cq_empty() Yuyang Du
2019-03-19 16:54 ` Bart Van Assche
2019-03-20 2:30 ` Yuyang Du
2019-03-18 8:57 ` [PATCH v2 16/19] locking/lockdep: Use function pointer to avoid constant checks Yuyang Du
2019-03-19 16:56 ` Bart Van Assche
2019-03-18 8:57 ` [PATCH v2 17/19] locking/lockdep: Combine check_noncircular and check_redundant Yuyang Du
2019-03-18 8:57 ` [PATCH v2 18/19] locking/lockdep: Update comments on dependency search Yuyang Du
2019-03-18 8:57 ` [PATCH v2 19/19] locking/lockdep: Change if to else-if when checking bfs errors Yuyang Du
2019-03-19 16:29 ` Bart Van Assche
2019-03-19 17:19 ` Joe Perches
2019-03-20 2:02 ` Yuyang Du
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190318085733.3143-4-duyuyang@gmail.com \
--to=duyuyang@gmail.com \
--cc=bvanassche@acm.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ming.lei@redhat.com \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).