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a11e1d432b
The poll() changes were not well thought out, and completely unexplained. They also caused a huge performance regression, because "->poll()" was no longer a trivial file operation that just called down to the underlying file operations, but instead did at least two indirect calls. Indirect calls are sadly slow now with the Spectre mitigation, but the performance problem could at least be largely mitigated by changing the "->get_poll_head()" operation to just have a per-file-descriptor pointer to the poll head instead. That gets rid of one of the new indirections. But that doesn't fix the new complexity that is completely unwarranted for the regular case. The (undocumented) reason for the poll() changes was some alleged AIO poll race fixing, but we don't make the common case slower and more complex for some uncommon special case, so this all really needs way more explanations and most likely a fundamental redesign. [ This revert is a revert of about 30 different commits, not reverted individually because that would just be unnecessarily messy - Linus ] Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
57 lines
1.6 KiB
C
57 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* net/atm/common.h - ATM sockets (common part for PVC and SVC) */
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/* Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA */
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#ifndef NET_ATM_COMMON_H
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#define NET_ATM_COMMON_H
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#include <linux/net.h>
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#include <linux/poll.h> /* for poll_table */
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int vcc_create(struct net *net, struct socket *sock, int protocol, int family, int kern);
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int vcc_release(struct socket *sock);
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int vcc_connect(struct socket *sock, int itf, short vpi, int vci);
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int vcc_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
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int flags);
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int vcc_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len);
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__poll_t vcc_poll(struct file *file, struct socket *sock, poll_table *wait);
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int vcc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
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int vcc_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg);
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int vcc_setsockopt(struct socket *sock, int level, int optname,
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char __user *optval, unsigned int optlen);
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int vcc_getsockopt(struct socket *sock, int level, int optname,
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char __user *optval, int __user *optlen);
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void vcc_process_recv_queue(struct atm_vcc *vcc);
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int atmpvc_init(void);
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void atmpvc_exit(void);
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int atmsvc_init(void);
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void atmsvc_exit(void);
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int atm_sysfs_init(void);
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void atm_sysfs_exit(void);
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#ifdef CONFIG_PROC_FS
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int atm_proc_init(void);
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void atm_proc_exit(void);
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#else
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static inline int atm_proc_init(void)
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{
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return 0;
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}
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static inline void atm_proc_exit(void)
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{
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/* nothing */
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}
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#endif /* CONFIG_PROC_FS */
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/* SVC */
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int svc_change_qos(struct atm_vcc *vcc,struct atm_qos *qos);
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void atm_dev_release_vccs(struct atm_dev *dev);
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#endif
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