[2.6 patch] the scheduled find_trylock_page() removal

[2.6 patch] the scheduled find_trylock_page() removal

[Adrian Bunk]

This patch contains the scheduled find_trylock_page() removal.

Signed-off-by: Adrian Bunk <bunk@stusta.de>

---

 Documentation/feature-removal-schedule.txt |   12 ------------
 include/linux/pagemap.h                    |    2 --
 mm/filemap.c                               |   20 --------------------
 3 files changed, 34 deletions(-)

--- linux-2.6.20-rc2-mm1/Documentation/feature-removal-schedule.txt.old	2007-01-02 21:34:57.000000000 +0100
+++ linux-2.6.20-rc2-mm1/Documentation/feature-removal-schedule.txt	2007-01-02 21:35:12.000000000 +0100
@@ -163,18 +163,6 @@
 
 ---------------------------
 
-What:	find_trylock_page
-When:	January 2007
-Why:	The interface no longer has any callers left in the kernel. It
-	is an odd interface (compared with other find_*_page functions), in
-	that it does not take a refcount to the page, only the page lock.
-	It should be replaced with find_get_page or find_lock_page if possible.
-	This feature removal can be reevaluated if users of the interface
-	cannot cleanly use something else.
-Who:	Nick Piggin <npiggin@suse.de>
-
----------------------------
-
 What:	Interrupt only SA_* flags
 When:	Januar 2007
 Why:	The interrupt related SA_* flags are replaced by IRQF_* to move them
--- linux-2.6.20-rc2-mm1/include/linux/pagemap.h.old	2007-01-02 21:35:20.000000000 +0100
+++ linux-2.6.20-rc2-mm1/include/linux/pagemap.h	2007-01-02 21:35:26.000000000 +0100
@@ -78,8 +78,6 @@
 				unsigned long index);
 extern struct page * find_lock_page(struct address_space *mapping,
 				unsigned long index);
-extern __deprecated_for_modules struct page * find_trylock_page(
-			struct address_space *mapping, unsigned long index);
 extern struct page * find_or_create_page(struct address_space *mapping,
 				unsigned long index, gfp_t gfp_mask);
 unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
--- linux-2.6.20-rc2-mm1/mm/filemap.c.old	2007-01-02 21:35:32.000000000 +0100
+++ linux-2.6.20-rc2-mm1/mm/filemap.c	2007-01-02 21:36:36.000000000 +0100
@@ -630,26 +630,6 @@
 EXPORT_SYMBOL(find_get_page);
 
 /**
- * find_trylock_page - find and lock a page
- * @mapping: the address_space to search
- * @offset: the page index
- *
- * Same as find_get_page(), but trylock it instead of incrementing the count.
- */
-struct page *find_trylock_page(struct address_space *mapping, unsigned long offset)
-{
-	struct page *page;
-
-	read_lock_irq(&mapping->tree_lock);
-	page = radix_tree_lookup(&mapping->page_tree, offset);
-	if (page && TestSetPageLocked(page))
-		page = NULL;
-	read_unlock_irq(&mapping->tree_lock);
-	return page;
-}
-EXPORT_SYMBOL(find_trylock_page);
-
-/**
  * find_lock_page - locate, pin and lock a pagecache page
  * @mapping: the address_space to search
  * @offset: the page index

Re: [2.6 patch] the scheduled find_trylock_page() removal

[Nick Piggin]

Adrian Bunk wrote:
> This patch contains the scheduled find_trylock_page() removal.
> 
> Signed-off-by: Adrian Bunk <bunk@stusta.de>

I guess I don't have a problem with this going into -mm and making its way
upstream sometime after the next release.

I would normally say it is OK to stay for another year because it is so
unintrusive, but I don't like the fact it doesn't give one an explicit ref
on the page -- it could be misused slightly more easily than find_lock_page
or find_get_page.

Anyone object? Otherwise:

Acked-by: Nick Piggin <npiggin@suse.de>

-- 
SUSE Labs, Novell Inc.
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Re: [2.6 patch] the scheduled find_trylock_page() removal

[Christoph Hellwig]

On Thu, Jan 04, 2007 at 03:53:07PM +1100, Nick Piggin wrote:
> Adrian Bunk wrote:
> >This patch contains the scheduled find_trylock_page() removal.
> >
> >Signed-off-by: Adrian Bunk <bunk@stusta.de>
> 
> I guess I don't have a problem with this going into -mm and making its way
> upstream sometime after the next release.
> 
> I would normally say it is OK to stay for another year because it is so
> unintrusive, but I don't like the fact it doesn't give one an explicit ref
> on the page -- it could be misused slightly more easily than find_lock_page
> or find_get_page.
> 
> Anyone object? Otherwise:

Just kill it.  There's absolutely no point in keeping dead code around.
It's bad enough we keep such things around for half a year.