[CIFS] Avoid extra large buffer allocation (and memcpy) in cifs_readpages (ec637e3f) · Commits · e / devices / android_kernel_fairphone_FP3

fs/cifs/cifs_debug.c

+19 −20

Original line number	Diff line number	Diff line
		@@ -401,8 +401,8 @@ static read_proc_t ntlmv2_enabled_read;
		static write_proc_t ntlmv2_enabled_write;
		static read_proc_t packet_signing_enabled_read;
		static write_proc_t packet_signing_enabled_write;
		static read_proc_t quotaEnabled_read;
		static write_proc_t quotaEnabled_write;
		static read_proc_t experimEnabled_read;
		static write_proc_t experimEnabled_write;
		static read_proc_t linuxExtensionsEnabled_read;
		static write_proc_t linuxExtensionsEnabled_write;

		@@ -442,9 +442,9 @@ cifs_proc_init(void)
		pde->write_proc = oplockEnabled_write;

		pde = create_proc_read_entry("Experimental", 0, proc_fs_cifs,
		quotaEnabled_read, NULL);
		experimEnabled_read, NULL);
		if (pde)
		pde->write_proc = quotaEnabled_write;
		pde->write_proc = experimEnabled_write;

		pde = create_proc_read_entry("LinuxExtensionsEnabled", 0, proc_fs_cifs,
		linuxExtensionsEnabled_read, NULL);
		@@ -586,14 +586,13 @@ oplockEnabled_write(struct file file, const char __user buffer,
		}

		static int
		quotaEnabled_read(char page, char *start, off_t off,
		experimEnabled_read(char page, char *start, off_t off,
		int count, int eof, void data)
		{
		int len;

		len = sprintf(page, "%d\n", experimEnabled);
		/* could also check if quotas are enabled in kernel
		as a whole first */

		len -= off;
		*start = page + off;

		@@ -608,7 +607,7 @@ quotaEnabled_read(char page, char *start, off_t off,
		return len;
		}
		static int
		quotaEnabled_write(struct file file, const char __user buffer,
		experimEnabled_write(struct file file, const char __user buffer,
		unsigned long count, void *data)
		{
		char c;
		@@ -621,6 +620,8 @@ quotaEnabled_write(struct file file, const char __user buffer,
		experimEnabled = 0;
		else if (c == '1' \|\| c == 'y' \|\| c == 'Y')
		experimEnabled = 1;
		else if (c == '2')
		experimEnabled = 2;

		return count;
		}
		@@ -632,8 +633,6 @@ linuxExtensionsEnabled_read(char page, char *start, off_t off,
		int len;

		len = sprintf(page, "%d\n", linuxExtEnabled);
		/* could also check if quotas are enabled in kernel
		as a whole first */
		len -= off;
		*start = page + off;

fs/cifs/cifsfs.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -733,7 +733,7 @@ cifs_init_request_bufs(void)
		kmem_cache_destroy(cifs_req_cachep);
		return -ENOMEM;
		}
		/* 256 (MAX_CIFS_HDR_SIZE bytes is enough for most SMB responses and
		/* MAX_CIFS_SMALL_BUFFER_SIZE bytes is enough for most SMB responses and
		almost all handle based requests (but not write response, nor is it
		sufficient for path based requests). A smaller size would have
		been more efficient (compacting multiple slab items on one 4k page)
		@@ -742,7 +742,8 @@ cifs_init_request_bufs(void)
		efficient to alloc 1 per page off the slab compared to 17K (5page)
		alloc of large cifs buffers even when page debugging is on */
		cifs_sm_req_cachep = kmem_cache_create("cifs_small_rq",
		MAX_CIFS_HDR_SIZE, 0, SLAB_HWCACHE_ALIGN, NULL, NULL);
		MAX_CIFS_SMALL_BUFFER_SIZE, 0, SLAB_HWCACHE_ALIGN,
		NULL, NULL);
		if (cifs_sm_req_cachep == NULL) {
		mempool_destroy(cifs_req_poolp);
		kmem_cache_destroy(cifs_req_cachep);

fs/cifs/cifsglob.h

+7 −1

Original line number	Diff line number	Diff line
		@@ -285,6 +285,7 @@ struct cifs_search_info {
		unsigned endOfSearch:1;
		unsigned emptyDir:1;
		unsigned unicode:1;
		unsigned smallBuf:1; /* so we know which buf_release function to call */
		};

		struct cifsFileInfo {
		@@ -420,7 +421,12 @@ struct dir_notify_req {
		#define MID_RESPONSE_RECEIVED 4
		#define MID_RETRY_NEEDED 8 /* session closed while this request out */
		#define MID_NO_RESP_NEEDED 0x10
		#define MID_SMALL_BUFFER 0x20 /* 112 byte response buffer instead of 4K */

		/* Types of response buffer returned from SendReceive2 */
		#define CIFS_NO_BUFFER 0 /* Response buffer not returned */
		#define CIFS_SMALL_BUFFER 1
		#define CIFS_LARGE_BUFFER 2
		#define CIFS_IOVEC 4 /* array of response buffers */

		/*
		*****************************************************************

fs/cifs/cifspdu.h

+5 −1

Original line number	Diff line number	Diff line
		@@ -80,7 +80,11 @@
		#define NT_TRANSACT_GET_USER_QUOTA 0x07
		#define NT_TRANSACT_SET_USER_QUOTA 0x08

		#define MAX_CIFS_HDR_SIZE 256 /* is future chained NTCreateXReadX bigger? */
		#define MAX_CIFS_SMALL_BUFFER_SIZE 448 /* big enough for most */
		/* future chained NTCreateXReadX bigger, but for time being NTCreateX biggest */
		/* among the requests (NTCreateX response is bigger with wct of 34) */
		#define MAX_CIFS_HDR_SIZE 0x58 /* 4 len + 32 hdr + (224 wct) + 2 bct + 2 pad /
		#define CIFS_SMALL_PATH 120 /* allows for (448-88)/3 */

		/* internal cifs vfs structures */
		/*****************************************************************

fs/cifs/cifsproto.h

+8 −6

Original line number	Diff line number	Diff line
		@@ -49,7 +49,7 @@ extern int SendReceive(const unsigned int /* xid / , struct cifsSesInfo ,
		int * /* bytes returned */ , const int long_op);
		extern int SendReceive2(const unsigned int /* xid / , struct cifsSesInfo ,
		struct kvec , int / nvec to send */,
		int * /* bytes returned */ , const int long_op);
		int * /* type of buf returned */ , const int long_op);
		extern int checkSMBhdr(struct smb_hdr *smb, __u16 mid);
		extern int checkSMB(struct smb_hdr *smb, __u16 mid, int length);
		extern int is_valid_oplock_break(struct smb_hdr *smb);
		@@ -94,7 +94,8 @@ extern int CIFSTCon(unsigned int xid, struct cifsSesInfo *ses,

		extern int CIFSFindFirst(const int xid, struct cifsTconInfo *tcon,
		const char searchName, const struct nls_table nls_codepage,
		__u16 searchHandle, struct cifs_search_info psrch_inf, int map, const char dirsep);
		__u16 searchHandle, struct cifs_search_info psrch_inf,
		int map, const char dirsep);

		extern int CIFSFindNext(const int xid, struct cifsTconInfo *tcon,
		__u16 searchHandle, struct cifs_search_info * psrch_inf);
		@@ -231,7 +232,8 @@ extern int CIFSSMBClose(const int xid, struct cifsTconInfo *tcon,

		extern int CIFSSMBRead(const int xid, struct cifsTconInfo *tcon,
		const int netfid, unsigned int count,
		const __u64 lseek, unsigned int nbytes, char *buf);
		const __u64 lseek, unsigned int nbytes, char *buf,
		int * return_buf_type);
		extern int CIFSSMBWrite(const int xid, struct cifsTconInfo *tcon,
		const int netfid, const unsigned int count,
		const __u64 lseek, unsigned int *nbytes,