xfs: Modify xlog_ticket_alloc() to use kernel's MM API

xlog_ticket_alloc() is always called under NOFS context, except from
unmount path, which eitherway is holding many FS locks, so, there is no
need for its callers to keep passing allocation flags into it.

change xlog_ticket_alloc() to use default kmem_cache_zalloc(), remove
its alloc_flags argument, and always use GFP_NOFS | __GFP_NOFAIL flags.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/xfs_log.c

@@ -433,7 +433,7 @@ xfs_log_reserve(
 	XFS_STATS_INC(mp, xs_try_logspace);
 
 	ASSERT(*ticp == NULL);
-	tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent, 0);
+	tic = xlog_ticket_alloc(log, unit_bytes, cnt, client, permanent);
 	*ticp = tic;
 
 	xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
@@ -3408,15 +3408,12 @@ xlog_ticket_alloc(
 	int			unit_bytes,
 	int			cnt,
 	char			client,
-	bool			permanent,
-	xfs_km_flags_t		alloc_flags)
+	bool			permanent)
 {
 	struct xlog_ticket	*tic;
 	int			unit_res;
 
-	tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
-	if (!tic)
-		return NULL;
+	tic = kmem_cache_zalloc(xfs_log_ticket_zone, GFP_NOFS | __GFP_NOFAIL);
 
 	unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
 

fs/xfs/xfs_log_cil.c

@@ -37,8 +37,7 @@ xlog_cil_ticket_alloc(
 {
 	struct xlog_ticket *tic;
 
-	tic = xlog_ticket_alloc(log, 0, 1, XFS_TRANSACTION, 0,
-				KM_NOFS);
+	tic = xlog_ticket_alloc(log, 0, 1, XFS_TRANSACTION, 0);
 
 	/*
 	 * set the current reservation to zero so we know to steal the basic

fs/xfs/xfs_log_priv.h

@@ -464,9 +464,7 @@ xlog_ticket_alloc(
 	int		unit_bytes,
 	int		count,
 	char		client,
-	bool		permanent,
-	xfs_km_flags_t	alloc_flags);
-
+	bool		permanent);
 
 static inline void
 xlog_write_adv_cnt(void **ptr, int *len, int *off, size_t bytes)