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[PATCH 20/32] x86/boot/e820: Clean up e820__setup_pci_gap()/e820_search_gap() a bit

Ingo Molnar posted 32 patches 7 months ago
[PATCH 20/32] x86/boot/e820: Clean up e820__setup_pci_gap()/e820_search_gap() a bit
Posted by Ingo Molnar 7 months ago 
Apply misc cleanups:

 - Use a bit more readable variable names, we haven't run out of
   underscore characters in the kernel yet.

 - s/0x400000/SZ_4M

 - s/1024*1024/SZ_1M

Suggested-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Ingo Molnar <mingo@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 | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index ee8b56605e4a..d00ca2dd20b7 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -680,7 +680,7 @@ static void __init e820__update_table_kexec(void)
 /*
  * Search for a gap in the E820 memory space from 0 to MAX_GAP_END (4GB).
  */
-static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsize)
+static int __init e820_search_gap(unsigned long *gap_start, unsigned long *gap_size)
 {
 	u64 last = MAX_GAP_END;
 	int idx = e820_table->nr_entries;
@@ -697,9 +697,9 @@ static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsiz
 		if (last > end) {
 			unsigned long gap = last - end;
 
-			if (gap >= *gapsize) {
-				*gapsize = gap;
-				*gapstart = end;
+			if (gap >= *gap_size) {
+				*gap_size = gap;
+				*gap_start = end;
 				found = 1;
 			}
 		}
@@ -719,29 +719,29 @@ static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsiz
  */
 __init void e820__setup_pci_gap(void)
 {
-	unsigned long gapstart, gapsize;
+	unsigned long gap_start, gap_size;
 	int found;
 
-	gapsize = 0x400000;
-	found  = e820_search_gap(&gapstart, &gapsize);
+	gap_size = SZ_4M;
+	found  = e820_search_gap(&gap_start, &gap_size);
 
 	if (!found) {
 #ifdef CONFIG_X86_64
-		gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
+		gap_start = (max_pfn << PAGE_SHIFT) + SZ_1M;
 		pr_err("Cannot find an available gap in the 32-bit address range\n");
 		pr_err("PCI devices with unassigned 32-bit BARs may not work!\n");
 #else
-		gapstart = 0x10000000;
+		gap_start = 0x10000000;
 #endif
 	}
 
 	/*
 	 * e820__reserve_resources_late() protects stolen RAM already:
 	 */
-	pci_mem_start = gapstart;
+	pci_mem_start = gap_start;
 
 	pr_info("[gap %#010lx-%#010lx] available for PCI devices\n",
-		gapstart, gapstart + gapsize - 1);
+		gap_start, gap_start + gap_size - 1);
 }
 
 /*
-- 
2.45.2
Re: [PATCH 20/32] x86/boot/e820: Clean up e820__setup_pci_gap()/e820_search_gap() a bit
Posted by Nikolay Borisov 6 months, 2 weeks ago 

On 5/15/25 15:05, Ingo Molnar wrote:
> Apply misc cleanups:
> 
>   - Use a bit more readable variable names, we haven't run out of
>     underscore characters in the kernel yet.
> 
>   - s/0x400000/SZ_4M
> 
>   - s/1024*1024/SZ_1M
> 
> Suggested-by: Andy Shevchenko <andy@kernel.org>
> Signed-off-by: Ingo Molnar <mingo@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 | 22 +++++++++++-----------
>   1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index ee8b56605e4a..d00ca2dd20b7 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -680,7 +680,7 @@ static void __init e820__update_table_kexec(void)
>   /*
>    * Search for a gap in the E820 memory space from 0 to MAX_GAP_END (4GB).
>    */
> -static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsize)
> +static int __init e820_search_gap(unsigned long *gap_start, unsigned long *gap_size)
>   {
>   	u64 last = MAX_GAP_END;
>   	int idx = e820_table->nr_entries;
> @@ -697,9 +697,9 @@ static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsiz
>   		if (last > end) {
>   			unsigned long gap = last - end;
>   
> -			if (gap >= *gapsize) {
> -				*gapsize = gap;
> -				*gapstart = end;
> +			if (gap >= *gap_size) {
> +				*gap_size = gap;
> +				*gap_start = end;
>   				found = 1;
>   			}
>   		}
> @@ -719,29 +719,29 @@ static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsiz
>    */
>   __init void e820__setup_pci_gap(void)
>   {
> -	unsigned long gapstart, gapsize;
> +	unsigned long gap_start, gap_size;
>   	int found;
>   
> -	gapsize = 0x400000;
> -	found  = e820_search_gap(&gapstart, &gapsize);
> +	gap_size = SZ_4M;
> +	found  = e820_search_gap(&gap_start, &gap_size);
>   
>   	if (!found) {
>   #ifdef CONFIG_X86_64
> -		gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
> +		gap_start = (max_pfn << PAGE_SHIFT) + SZ_1M;
>   		pr_err("Cannot find an available gap in the 32-bit address range\n");
>   		pr_err("PCI devices with unassigned 32-bit BARs may not work!\n");
>   #else
> -		gapstart = 0x10000000;
> +		gap_start = 0x10000000;

nit: gap_start = SZ_256M;

>   #endif
>   	}
>   
>   	/*
>   	 * e820__reserve_resources_late() protects stolen RAM already:
>   	 */
> -	pci_mem_start = gapstart;
> +	pci_mem_start = gap_start;
>   
>   	pr_info("[gap %#010lx-%#010lx] available for PCI devices\n",
> -		gapstart, gapstart + gapsize - 1);
> +		gap_start, gap_start + gap_size - 1);
>   }
>   
>   /*
[tip: x86/boot] x86/boot/e820: Clean up e820__setup_pci_gap()/e820_search_gap() a bit
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:     cff02bff04f237b361fdc7066f043d00f0e3c872
Gitweb:        https://git.kernel.org/tip/cff02bff04f237b361fdc7066f043d00f0e3c872
Author:        Ingo Molnar <mingo@kernel.org>
AuthorDate:    Thu, 15 May 2025 14:05:36 +02:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Sun, 14 Dec 2025 09:19:40 +01:00

x86/boot/e820: Clean up e820__setup_pci_gap()/e820_search_gap() a bit

Apply misc cleanups:

 - Use a bit more readable variable names, we haven't run out of
   underscore characters in the kernel yet.

 - s/0x400000/SZ_4M

 - s/1024*1024/SZ_1M

Suggested-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: H . Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20250515120549.2820541-21-mingo@kernel.org
---
 arch/x86/kernel/e820.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 39f29bf..b8edc5e 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -638,7 +638,7 @@ static void __init e820__update_table_kexec(void)
 /*
  * Search for a gap in the E820 memory space from 0 to MAX_GAP_END (4GB).
  */
-static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsize)
+static int __init e820_search_gap(unsigned long *gap_start, unsigned long *gap_size)
 {
 	u64 last = MAX_GAP_END;
 	int idx = e820_table->nr_entries;
@@ -655,9 +655,9 @@ static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsiz
 		if (last > end) {
 			unsigned long gap = last - end;
 
-			if (gap >= *gapsize) {
-				*gapsize = gap;
-				*gapstart = end;
+			if (gap >= *gap_size) {
+				*gap_size = gap;
+				*gap_start = end;
 				found = 1;
 			}
 		}
@@ -677,29 +677,29 @@ static int __init e820_search_gap(unsigned long *gapstart, unsigned long *gapsiz
  */
 __init void e820__setup_pci_gap(void)
 {
-	unsigned long gapstart, gapsize;
+	unsigned long gap_start, gap_size;
 	int found;
 
-	gapsize = 0x400000;
-	found  = e820_search_gap(&gapstart, &gapsize);
+	gap_size = SZ_4M;
+	found  = e820_search_gap(&gap_start, &gap_size);
 
 	if (!found) {
 #ifdef CONFIG_X86_64
-		gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024;
+		gap_start = (max_pfn << PAGE_SHIFT) + SZ_1M;
 		pr_err("Cannot find an available gap in the 32-bit address range\n");
 		pr_err("PCI devices with unassigned 32-bit BARs may not work!\n");
 #else
-		gapstart = 0x10000000;
+		gap_start = 0x10000000;
 #endif
 	}
 
 	/*
 	 * e820__reserve_resources_late() protects stolen RAM already:
 	 */
-	pci_mem_start = gapstart;
+	pci_mem_start = gap_start;
 
 	pr_info("[gap %#010lx-%#010lx] available for PCI devices\n",
-		gapstart, gapstart + gapsize - 1);
+		gap_start, gap_start + gap_size - 1);
 }
 
 /*

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