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Commit 73d03931 authored by Gao Xiang's avatar Gao Xiang Committed by Greg Kroah-Hartman
Browse files

erofs: kill use_vmap module parameter 

As Christoph said [1],
"vm_map_ram is supposed to generally behave better.  So if
it doesn't please report that that to the arch maintainer
and linux-mm so that they can look into the issue.  Having
user make choices of deep down kernel internals is just
a horrible interface.

Please talk to maintainers of other bits of the kernel
if you see issues and / or need enhancements. "

Let's redo the previous conclusion and kill the vmap
approach.

[1] https://lore.kernel.org/r/20190830165533.GA10909@infradead.org/


Reported-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarGao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190904020912.63925-21-gaoxiang25@huawei.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e2c71e74

Documentation/filesystems/erofs.txt

+0 −4
Original line number Diff line number Diff line
@@ -67,10 +67,6 @@ cache_strategy=%s Select a strategy for cached decompression from now on: 
                                   It still does in-place I/O decompression

                                   for the rest compressed physical clusters.



Module parameters

=================

use_vmap=[0|1]         Use vmap() instead of vm_map_ram() (default 0).



On-disk details

===============

fs/erofs/decompressor.c

+13 −33
Original line number Diff line number Diff line
@@ -28,10 +28,6 @@ struct z_erofs_decompressor { 
	char *name;

};



static bool use_vmap;

module_param(use_vmap, bool, 0444);

MODULE_PARM_DESC(use_vmap, "Use vmap() instead of vm_map_ram() (default 0)");



static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,

					 struct list_head *pagepool)

{
@@ -221,32 +217,6 @@ static void copy_from_pcpubuf(struct page **out, const char *dst, 
	}

}



static void *erofs_vmap(struct page **pages, unsigned int count)

{

	int i = 0;



	if (use_vmap)

		return vmap(pages, count, VM_MAP, PAGE_KERNEL);



	while (1) {

		void *addr = vm_map_ram(pages, count, -1, PAGE_KERNEL);



		/* retry two more times (totally 3 times) */

		if (addr || ++i >= 3)

			return addr;

		vm_unmap_aliases();

	}

	return NULL;

}



static void erofs_vunmap(const void *mem, unsigned int count)

{

	if (!use_vmap)

		vm_unmap_ram(mem, count);

	else

		vunmap(mem);

}



static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,

				      struct list_head *pagepool)

{
@@ -255,7 +225,7 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq, 
	const struct z_erofs_decompressor *alg = decompressors + rq->alg;

	unsigned int dst_maptype;

	void *dst;

	int ret;

	int ret, i;



	if (nrpages_out == 1 && !rq->inplace_io) {

		DBG_BUGON(!*rq->out);
@@ -293,9 +263,19 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq, 
		goto dstmap_out;

	}



	dst = erofs_vmap(rq->out, nrpages_out);

	i = 0;

	while (1) {

		dst = vm_map_ram(rq->out, nrpages_out, -1, PAGE_KERNEL);



		/* retry two more times (totally 3 times) */

		if (dst || ++i >= 3)

			break;

		vm_unmap_aliases();

	}



	if (!dst)

		return -ENOMEM;



	dst_maptype = 2;



dstmap_out:
@@ -304,7 +284,7 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq, 
	if (!dst_maptype)

		kunmap_atomic(dst);

	else if (dst_maptype == 2)

		erofs_vunmap(dst, nrpages_out);

		vm_unmap_ram(dst, nrpages_out);

	return ret;

}