[v1] x86/boot/e820: Assorted E820 table handling features and cleanups

[PATCH 01/32] x86/boot/e820: Remove inverted boolean logic from the e820_nomerge() function name, rename it to e820_type_mergeable()

Posted by Ingo Molnar 7 months ago

It's a bad practice to put inverted logic into function names,
flip it back and rename it to e820_type_mergeable().

Add/update a few comments about this function while at it.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Shevchenko <andy@kernel.org>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 arch/x86/kernel/e820.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 9920122018a0..b95f0519a877 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -304,18 +304,22 @@ static int __init cpcompare(const void *a, const void *b)
 	return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
 }
 
-static bool e820_nomerge(enum e820_type type)
+/*
+ * Can two consecutive E820 entries of this same E820 type be merged?
+ */
+static bool e820_type_mergeable(enum e820_type type)
 {
 	/*
 	 * These types may indicate distinct platform ranges aligned to
-	 * numa node, protection domain, performance domain, or other
+	 * NUMA node, protection domain, performance domain, or other
 	 * boundaries. Do not merge them.
 	 */
 	if (type == E820_TYPE_PRAM)
-		return true;
+		return false;
 	if (type == E820_TYPE_SOFT_RESERVED)
-		return true;
-	return false;
+		return false;
+
+	return true;
 }
 
 int __init e820__update_table(struct e820_table *table)
@@ -393,7 +397,7 @@ int __init e820__update_table(struct e820_table *table)
 		}
 
 		/* Continue building up new map based on this information: */
-		if (current_type != last_type || e820_nomerge(current_type)) {
+		if (current_type != last_type || !e820_type_mergeable(current_type)) {
 			if (last_type) {
 				new_entries[new_nr_entries].size = change_point[chg_idx]->addr - last_addr;
 				/* Move forward only if the new size was non-zero: */
-- 
2.45.2

Re: [PATCH 01/32] x86/boot/e820: Remove inverted boolean logic from the e820_nomerge() function name, rename it to e820_type_mergeable()

Posted by Nikolay Borisov 6 months, 2 weeks ago


On 5/15/25 15:05, Ingo Molnar wrote:
> It's a bad practice to put inverted logic into function names,
> flip it back and rename it to e820_type_mergeable().
> 
> Add/update a few comments about this function while at it.
> 
> Signed-off-by: Ingo Molnar <mingo@kernel.org>
> Cc: Andy Shevchenko <andy@kernel.org>
> Cc: Arnd Bergmann <arnd@kernel.org>
> Cc: David Woodhouse <dwmw@amazon.co.uk>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>

Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>

[tip: x86/boot] x86/boot/e820: Remove inverted boolean logic from the e820_nomerge() function name, rename it to e820_type_mergeable()

Posted by tip-bot2 for Ingo Molnar 2 days, 18 hours ago

The following commit has been merged into the x86/boot branch of tip:

Commit-ID:     db0d69c5700ba4749217b83b475606d864d46226
Gitweb:        https://git.kernel.org/tip/db0d69c5700ba4749217b83b475606d864d46226
Author:        Ingo Molnar <mingo@kernel.org>
AuthorDate:    Thu, 15 May 2025 14:05:17 +02:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Sun, 14 Dec 2025 09:19:36 +01:00

x86/boot/e820: Remove inverted boolean logic from the e820_nomerge() function name, rename it to e820_type_mergeable()

It's a bad practice to put inverted logic into function names,
flip it back and rename it to e820_type_mergeable().

Add/update a few comments about this function while at it.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Link: https://patch.msgid.link/20250515120549.2820541-2-mingo@kernel.org
---
 arch/x86/kernel/e820.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index b15b97d..4c3159d 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -305,18 +305,22 @@ static int __init cpcompare(const void *a, const void *b)
 	return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
 }
 
-static bool e820_nomerge(enum e820_type type)
+/*
+ * Can two consecutive E820 entries of this same E820 type be merged?
+ */
+static bool e820_type_mergeable(enum e820_type type)
 {
 	/*
 	 * These types may indicate distinct platform ranges aligned to
-	 * numa node, protection domain, performance domain, or other
+	 * NUMA node, protection domain, performance domain, or other
 	 * boundaries. Do not merge them.
 	 */
 	if (type == E820_TYPE_PRAM)
-		return true;
+		return false;
 	if (type == E820_TYPE_SOFT_RESERVED)
-		return true;
-	return false;
+		return false;
+
+	return true;
 }
 
 int __init e820__update_table(struct e820_table *table)
@@ -394,7 +398,7 @@ int __init e820__update_table(struct e820_table *table)
 		}
 
 		/* Continue building up new map based on this information: */
-		if (current_type != last_type || e820_nomerge(current_type)) {
+		if (current_type != last_type || !e820_type_mergeable(current_type)) {
 			if (last_type) {
 				new_entries[new_nr_entries].size = change_point[chg_idx]->addr - last_addr;
 				/* Move forward only if the new size was non-zero: */